/**
 * @license Copyright (c) 2003-2018, CKSource - Frederico Knabben. All rights reserved.
 * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license
 */

/**
 * @fileOverview The floating dialog plugin.
 */

/**
 * No resize for this dialog.
 *
 * @readonly
 * @property {Number} [=0]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_RESIZE_NONE = 0;

/**
 * Only allow horizontal resizing for this dialog, disable vertical resizing.
 *
 * @readonly
 * @property {Number} [=1]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_RESIZE_WIDTH = 1;

/**
 * Only allow vertical resizing for this dialog, disable horizontal resizing.
 *
 * @readonly
 * @property {Number} [=2]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_RESIZE_HEIGHT = 2;

/**
 * Allow the dialog to be resized in both directions.
 *
 * @readonly
 * @property {Number} [=3]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_RESIZE_BOTH = 3;

/**
 * Dialog state when idle.
 *
 * @readonly
 * @property {Number} [=1]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_STATE_IDLE = 1;

/**
 * Dialog state when busy.
 *
 * @readonly
 * @property {Number} [=2]
 * @member CKEDITOR
 */
CKEDITOR.DIALOG_STATE_BUSY = 2;

( function() {
	var cssLength = CKEDITOR.tools.cssLength;

	function isTabVisible( tabId ) {
		return !!this._.tabs[ tabId ][ 0 ].$.offsetHeight;
	}

	function getPreviousVisibleTab() {
		var tabId = this._.currentTabId,
			length = this._.tabIdList.length,
			tabIndex = CKEDITOR.tools.indexOf( this._.tabIdList, tabId ) + length;

		for ( var i = tabIndex - 1; i > tabIndex - length; i-- ) {
			if ( isTabVisible.call( this, this._.tabIdList[ i % length ] ) )
				return this._.tabIdList[ i % length ];
		}

		return null;
	}

	function getNextVisibleTab() {
		var tabId = this._.currentTabId,
			length = this._.tabIdList.length,
			tabIndex = CKEDITOR.tools.indexOf( this._.tabIdList, tabId );

		for ( var i = tabIndex + 1; i < tabIndex + length; i++ ) {
			if ( isTabVisible.call( this, this._.tabIdList[ i % length ] ) )
				return this._.tabIdList[ i % length ];
		}

		return null;
	}


	function clearOrRecoverTextInputValue( container, isRecover ) {
		var inputs = container.$.getElementsByTagName( 'input' );
		for ( var i = 0, length = inputs.length; i < length; i++ ) {
			var item = new CKEDITOR.dom.element( inputs[ i ] );

			if ( item.getAttribute( 'type' ).toLowerCase() == 'text' ) {
				if ( isRecover ) {
					item.setAttribute( 'value', item.getCustomData( 'fake_value' ) || '' );
					item.removeCustomData( 'fake_value' );
				} else {
					item.setCustomData( 'fake_value', item.getAttribute( 'value' ) );
					item.setAttribute( 'value', '' );
				}
			}
		}
	}

	// Handle dialog element validation state UI changes.
	function handleFieldValidated( isValid, msg ) {
		var input = this.getInputElement();
		if ( input )
			isValid ? input.removeAttribute( 'aria-invalid' ) : input.setAttribute( 'aria-invalid', true );

		if ( !isValid ) {
			if ( this.select )
				this.select();
			else
				this.focus();
		}

		msg && alert( msg ); // jshint ignore:line

		this.fire( 'validated', { valid: isValid, msg: msg } );
	}

	function resetField() {
		var input = this.getInputElement();
		input && input.removeAttribute( 'aria-invalid' );
	}

	var templateSource = '<div class="cke_reset_all {editorId} {editorDialogClass} {hidpi}' +
		'" dir="{langDir}"' +
		' lang="{langCode}"' +
		' role="dialog"' +
		' aria-labelledby="cke_dialog_title_{id}"' +
		'>' +
		'<table class="cke_dialog ' + CKEDITOR.env.cssClass + ' cke_{langDir}"' +
			' style="position:absolute" role="presentation">' +
			'<tr><td role="presentation">' +
			'<div class="cke_dialog_body" role="presentation">' +
				'<div id="cke_dialog_title_{id}" class="cke_dialog_title" role="presentation"></div>' +
				'<a id="cke_dialog_close_button_{id}" class="cke_dialog_close_button" href="javascript:void(0)" title="{closeTitle}" role="button"><span class="cke_label">X</span></a>' +
				'<div id="cke_dialog_tabs_{id}" class="cke_dialog_tabs" role="tablist"></div>' +
				'<table class="cke_dialog_contents" role="presentation">' +
				'<tr>' +
					'<td id="cke_dialog_contents_{id}" class="cke_dialog_contents_body" role="presentation"></td>' +
				'</tr>' +
				'<tr>' +
					'<td id="cke_dialog_footer_{id}" class="cke_dialog_footer" role="presentation"></td>' +
				'</tr>' +
				'</table>' +
			'</div>' +
			'</td></tr>' +
		'</table>' +
		'</div>';

	function buildDialog( editor ) {
		var element = CKEDITOR.dom.element.createFromHtml( CKEDITOR.addTemplate( 'dialog', templateSource ).output( {
			id: CKEDITOR.tools.getNextNumber(),
			editorId: editor.id,
			langDir: editor.lang.dir,
			langCode: editor.langCode,
			editorDialogClass: 'cke_editor_' + editor.name.replace( /\./g, '\\.' ) + '_dialog',
			closeTitle: editor.lang.common.close,
			hidpi: CKEDITOR.env.hidpi ? 'cke_hidpi' : ''
		} ) );

		// TODO: Change this to getById(), so it'll support custom templates.
		var body = element.getChild( [ 0, 0, 0, 0, 0 ] ),
			title = body.getChild( 0 ),
			close = body.getChild( 1 );

		// Don't allow dragging on dialog (https://dev.ckeditor.com/ticket/13184).
		editor.plugins.clipboard && CKEDITOR.plugins.clipboard.preventDefaultDropOnElement( body );

		// IFrame shim for dialog that masks activeX in IE. (https://dev.ckeditor.com/ticket/7619)
		if ( CKEDITOR.env.ie && !CKEDITOR.env.quirks && !CKEDITOR.env.edge ) {
			var src = 'javascript:void(function(){' + encodeURIComponent( 'document.open();(' + CKEDITOR.tools.fixDomain + ')();document.close();' ) + '}())', // jshint ignore:line
				iframe = CKEDITOR.dom.element.createFromHtml( '<iframe' +
					' frameBorder="0"' +
					' class="cke_iframe_shim"' +
					' src="' + src + '"' +
					' tabIndex="-1"' +
					'></iframe>' );
			iframe.appendTo( body.getParent() );
		}

		// Make the Title and Close Button unselectable.
		title.unselectable();
		close.unselectable();

		return {
			element: element,
			parts: {
				dialog: element.getChild( 0 ),
				title: title,
				close: close,
				tabs: body.getChild( 2 ),
				contents: body.getChild( [ 3, 0, 0, 0 ] ),
				footer: body.getChild( [ 3, 0, 1, 0 ] )
			}
		};
	}

	/**
	 * This is the base class for runtime dialog objects. An instance of this
	 * class represents a single named dialog for a single editor instance.
	 *
	 *		var dialogObj = new CKEDITOR.dialog( editor, 'smiley' );
	 *
	 * @class
	 * @constructor Creates a dialog class instance.
	 * @param {Object} editor The editor which created the dialog.
	 * @param {String} dialogName The dialog's registered name.
	 */
	CKEDITOR.dialog = function( editor, dialogName ) {
		// Load the dialog definition.
		var definition = CKEDITOR.dialog._.dialogDefinitions[ dialogName ],
			defaultDefinition = CKEDITOR.tools.clone( defaultDialogDefinition ),
			buttonsOrder = editor.config.dialog_buttonsOrder || 'OS',
			dir = editor.lang.dir,
			tabsToRemove = {},
			i, processed, stopPropagation;

		if ( ( buttonsOrder == 'OS' && CKEDITOR.env.mac ) || // The buttons in MacOS Apps are in reverse order (https://dev.ckeditor.com/ticket/4750)
		( buttonsOrder == 'rtl' && dir == 'ltr' ) || ( buttonsOrder == 'ltr' && dir == 'rtl' ) )
			defaultDefinition.buttons.reverse();


		// Completes the definition with the default values.
		definition = CKEDITOR.tools.extend( definition( editor ), defaultDefinition );

		// Clone a functionally independent copy for this dialog.
		definition = CKEDITOR.tools.clone( definition );

		// Create a complex definition object, extending it with the API
		// functions.
		definition = new definitionObject( this, definition );

		var themeBuilt = buildDialog( editor );

		// Initialize some basic parameters.
		this._ = {
			editor: editor,
			element: themeBuilt.element,
			name: dialogName,
			contentSize: { width: 0, height: 0 },
			size: { width: 0, height: 0 },
			contents: {},
			buttons: {},
			accessKeyMap: {},

			// Initialize the tab and page map.
			tabs: {},
			tabIdList: [],
			currentTabId: null,
			currentTabIndex: null,
			pageCount: 0,
			lastTab: null,
			tabBarMode: false,

			// Initialize the tab order array for input widgets.
			focusList: [],
			currentFocusIndex: 0,
			hasFocus: false
		};

		this.parts = themeBuilt.parts;

		CKEDITOR.tools.setTimeout( function() {
			editor.fire( 'ariaWidget', this.parts.contents );
		}, 0, this );

		// Set the startup styles for the dialog, avoiding it enlarging the
		// page size on the dialog creation.
		var startStyles = {
			position: CKEDITOR.env.ie6Compat ? 'absolute' : 'fixed',
			top: 0,
			visibility: 'hidden'
		};

		startStyles[ dir == 'rtl' ? 'right' : 'left' ] = 0;
		this.parts.dialog.setStyles( startStyles );


		// Call the CKEDITOR.event constructor to initialize this instance.
		CKEDITOR.event.call( this );

		// Fire the "dialogDefinition" event, making it possible to customize
		// the dialog definition.
		this.definition = definition = CKEDITOR.fire( 'dialogDefinition', {
			name: dialogName,
			definition: definition
		}, editor ).definition;

		// Cache tabs that should be removed.
		if ( !( 'removeDialogTabs' in editor._ ) && editor.config.removeDialogTabs ) {
			var removeContents = editor.config.removeDialogTabs.split( ';' );

			for ( i = 0; i < removeContents.length; i++ ) {
				var parts = removeContents[ i ].split( ':' );
				if ( parts.length == 2 ) {
					var removeDialogName = parts[ 0 ];
					if ( !tabsToRemove[ removeDialogName ] )
						tabsToRemove[ removeDialogName ] = [];
					tabsToRemove[ removeDialogName ].push( parts[ 1 ] );
				}
			}
			editor._.removeDialogTabs = tabsToRemove;
		}

		// Remove tabs of this dialog.
		if ( editor._.removeDialogTabs && ( tabsToRemove = editor._.removeDialogTabs[ dialogName ] ) ) {
			for ( i = 0; i < tabsToRemove.length; i++ )
				definition.removeContents( tabsToRemove[ i ] );
		}

		// Initialize load, show, hide, ok and cancel events.
		if ( definition.onLoad )
			this.on( 'load', definition.onLoad );

		if ( definition.onShow )
			this.on( 'show', definition.onShow );

		if ( definition.onHide )
			this.on( 'hide', definition.onHide );

		if ( definition.onOk ) {
			this.on( 'ok', function( evt ) {
				// Dialog confirm might probably introduce content changes (https://dev.ckeditor.com/ticket/5415).
				editor.fire( 'saveSnapshot' );
				setTimeout( function() {
					editor.fire( 'saveSnapshot' );
				}, 0 );
				if ( definition.onOk.call( this, evt ) === false )
					evt.data.hide = false;
			} );
		}

		// Set default dialog state.
		this.state = CKEDITOR.DIALOG_STATE_IDLE;

		if ( definition.onCancel ) {
			this.on( 'cancel', function( evt ) {
				if ( definition.onCancel.call( this, evt ) === false )
					evt.data.hide = false;
			} );
		}

		var me = this;

		// Iterates over all items inside all content in the dialog, calling a
		// function for each of them.
		var iterContents = function( func ) {
				var contents = me._.contents,
					stop = false;

				for ( var i in contents ) {
					for ( var j in contents[ i ] ) {
						stop = func.call( this, contents[ i ][ j ] );
						if ( stop )
							return;
					}
				}
			};

		this.on( 'ok', function( evt ) {
			iterContents( function( item ) {
				if ( item.validate ) {
					var retval = item.validate( this ),
						invalid = ( typeof retval == 'string' ) || retval === false;

					if ( invalid ) {
						evt.data.hide = false;
						evt.stop();
					}

					handleFieldValidated.call( item, !invalid, typeof retval == 'string' ? retval : undefined );
					return invalid;
				}
			} );
		}, this, null, 0 );

		this.on( 'cancel', function( evt ) {
			iterContents( function( item ) {
				if ( item.isChanged() ) {
					if ( !editor.config.dialog_noConfirmCancel && !confirm( editor.lang.common.confirmCancel ) ) // jshint ignore:line
						evt.data.hide = false;
					return true;
				}
			} );
		}, this, null, 0 );

		this.parts.close.on( 'click', function( evt ) {
			if ( this.fire( 'cancel', { hide: true } ).hide !== false )
				this.hide();
			evt.data.preventDefault();
		}, this );

		// Sort focus list according to tab order definitions.
		function setupFocus() {
			var focusList = me._.focusList;
			focusList.sort( function( a, b ) {
				// Mimics browser tab order logics;
				if ( a.tabIndex != b.tabIndex )
					return b.tabIndex - a.tabIndex;
				//  Sort is not stable in some browsers,
				// fall-back the comparator to 'focusIndex';
				else
					return a.focusIndex - b.focusIndex;
			} );

			var size = focusList.length;
			for ( var i = 0; i < size; i++ )
				focusList[ i ].focusIndex = i;
		}

		// Expects 1 or -1 as an offset, meaning direction of the offset change.
		function changeFocus( offset ) {
			var focusList = me._.focusList;
			offset = offset || 0;

			if ( focusList.length < 1 )
				return;

			var startIndex = me._.currentFocusIndex;

			if ( me._.tabBarMode && offset < 0 ) {
				// If we are in tab mode, we need to mimic that we started tabbing back from the first
				// focusList (so it will go to the last one).
				startIndex = 0;
			}

			// Trigger the 'blur' event of  any input element before anything,
			// since certain UI updates may depend on it.
			try {
				focusList[ startIndex ].getInputElement().$.blur();
			} catch ( e ) {}

			var currentIndex = startIndex,
				hasTabs = me._.pageCount > 1;

			do {
				currentIndex = currentIndex + offset;

				if ( hasTabs && !me._.tabBarMode && ( currentIndex == focusList.length || currentIndex == -1 ) ) {
					// If the dialog was not in tab mode, then focus the first tab (https://dev.ckeditor.com/ticket/13027).
					me._.tabBarMode = true;
					me._.tabs[ me._.currentTabId ][ 0 ].focus();
					me._.currentFocusIndex = -1;

					// Early return, in order to avoid accessing focusList[ -1 ].
					return;
				}

				currentIndex = ( currentIndex + focusList.length ) % focusList.length;

				if ( currentIndex == startIndex ) {
					break;
				}
			} while ( offset && !focusList[ currentIndex ].isFocusable() );

			focusList[ currentIndex ].focus();

			// Select whole field content.
			if ( focusList[ currentIndex ].type == 'text' )
				focusList[ currentIndex ].select();
		}

		this.changeFocus = changeFocus;


		function keydownHandler( evt ) {
			// If I'm not the top dialog, ignore.
			if ( me != CKEDITOR.dialog._.currentTop )
				return;

			var keystroke = evt.data.getKeystroke(),
				rtl = editor.lang.dir == 'rtl',
				arrowKeys = [ 37, 38, 39, 40 ],
				button;

			processed = stopPropagation = 0;

			if ( keystroke == 9 || keystroke == CKEDITOR.SHIFT + 9 ) {
				var shiftPressed = ( keystroke == CKEDITOR.SHIFT + 9 );
				changeFocus( shiftPressed ? -1 : 1 );
				processed = 1;
			} else if ( keystroke == CKEDITOR.ALT + 121 && !me._.tabBarMode && me.getPageCount() > 1 ) {
				// Alt-F10 puts focus into the current tab item in the tab bar.
				me._.tabBarMode = true;
				me._.tabs[ me._.currentTabId ][ 0 ].focus();
				me._.currentFocusIndex = -1;
				processed = 1;
			} else if ( CKEDITOR.tools.indexOf( arrowKeys, keystroke ) != -1 && me._.tabBarMode ) {
				// Array with key codes that activate previous tab.
				var prevKeyCodes = [
						// Depending on the lang dir: right or left key
						rtl ? 39 : 37,
						// Top/bot arrow: actually for both cases it's the same.
						38
					],
					nextId = CKEDITOR.tools.indexOf( prevKeyCodes, keystroke ) != -1 ? getPreviousVisibleTab.call( me ) : getNextVisibleTab.call( me );

				me.selectPage( nextId );
				me._.tabs[ nextId ][ 0 ].focus();
				processed = 1;
			} else if ( ( keystroke == 13 || keystroke == 32 ) && me._.tabBarMode ) {
				this.selectPage( this._.currentTabId );
				this._.tabBarMode = false;
				this._.currentFocusIndex = -1;
				changeFocus( 1 );
				processed = 1;
			}
			// If user presses enter key in a text box, it implies clicking OK for the dialog.
			else if ( keystroke == 13 /*ENTER*/ ) {
				// Don't do that for a target that handles ENTER.
				var target = evt.data.getTarget();
				if ( !target.is( 'a', 'button', 'select', 'textarea' ) && ( !target.is( 'input' ) || target.$.type != 'button' ) ) {
					button = this.getButton( 'ok' );
					button && CKEDITOR.tools.setTimeout( button.click, 0, button );
					processed = 1;
				}
				stopPropagation = 1; // Always block the propagation (https://dev.ckeditor.com/ticket/4269)
			} else if ( keystroke == 27 /*ESC*/ ) {
				button = this.getButton( 'cancel' );

				// If there's a Cancel button, click it, else just fire the cancel event and hide the dialog.
				if ( button )
					CKEDITOR.tools.setTimeout( button.click, 0, button );
				else {
					if ( this.fire( 'cancel', { hide: true } ).hide !== false )
						this.hide();
				}
				stopPropagation = 1; // Always block the propagation (https://dev.ckeditor.com/ticket/4269)
			} else {
				return;
			}

			keypressHandler( evt );
		}

		function keypressHandler( evt ) {
			if ( processed )
				evt.data.preventDefault( 1 );
			else if ( stopPropagation )
				evt.data.stopPropagation();
		}

		var dialogElement = this._.element;

		editor.focusManager.add( dialogElement, 1 );

		// Add the dialog keyboard handlers.
		this.on( 'show', function() {
			dialogElement.on( 'keydown', keydownHandler, this );

			// Some browsers instead, don't cancel key events in the keydown, but in the
			// keypress. So we must do a longer trip in those cases. (https://dev.ckeditor.com/ticket/4531,https://dev.ckeditor.com/ticket/8985)
			if ( CKEDITOR.env.gecko )
				dialogElement.on( 'keypress', keypressHandler, this );

		} );
		this.on( 'hide', function() {
			dialogElement.removeListener( 'keydown', keydownHandler );
			if ( CKEDITOR.env.gecko )
				dialogElement.removeListener( 'keypress', keypressHandler );

			// Reset fields state when closing dialog.
			iterContents( function( item ) {
				resetField.apply( item );
			} );
		} );
		this.on( 'iframeAdded', function( evt ) {
			var doc = new CKEDITOR.dom.document( evt.data.iframe.$.contentWindow.document );
			doc.on( 'keydown', keydownHandler, this, null, 0 );
		} );

		// Auto-focus logic in dialog.
		this.on( 'show', function() {
			// Setup tabIndex on showing the dialog instead of on loading
			// to allow dynamic tab order happen in dialog definition.
			setupFocus();

			var hasTabs = me._.pageCount > 1;

			if ( editor.config.dialog_startupFocusTab && hasTabs ) {
				me._.tabBarMode = true;
				me._.tabs[ me._.currentTabId ][ 0 ].focus();
				me._.currentFocusIndex = -1;
			} else if ( !this._.hasFocus ) {
				// https://dev.ckeditor.com/ticket/13114#comment:4.
				this._.currentFocusIndex = hasTabs ? -1 : this._.focusList.length - 1;

				// Decide where to put the initial focus.
				if ( definition.onFocus ) {
					var initialFocus = definition.onFocus.call( this );
					// Focus the field that the user specified.
					initialFocus && initialFocus.focus();
				}
				// Focus the first field in layout order.
				else {
					changeFocus( 1 );
				}
			}
		}, this, null, 0xffffffff );

		// IE6 BUG: Text fields and text areas are only half-rendered the first time the dialog appears in IE6 (https://dev.ckeditor.com/ticket/2661).
		// This is still needed after [2708] and [2709] because text fields in hidden TR tags are still broken.
		if ( CKEDITOR.env.ie6Compat ) {
			this.on( 'load', function() {
				var outer = this.getElement(),
					inner = outer.getFirst();
				inner.remove();
				inner.appendTo( outer );
			}, this );
		}

		initDragAndDrop( this );
		initResizeHandles( this );

		// Insert the title.
		( new CKEDITOR.dom.text( definition.title, CKEDITOR.document ) ).appendTo( this.parts.title );

		// Insert the tabs and contents.
		for ( i = 0; i < definition.contents.length; i++ ) {
			var page = definition.contents[ i ];
			page && this.addPage( page );
		}

		this.parts.tabs.on( 'click', function( evt ) {
			var target = evt.data.getTarget();
			// If we aren't inside a tab, bail out.
			if ( target.hasClass( 'cke_dialog_tab' ) ) {
				// Get the ID of the tab, without the 'cke_' prefix and the unique number suffix.
				var id = target.$.id;
				this.selectPage( id.substring( 4, id.lastIndexOf( '_' ) ) );

				if ( this._.tabBarMode ) {
					this._.tabBarMode = false;
					this._.currentFocusIndex = -1;
					changeFocus( 1 );
				}
				evt.data.preventDefault();
			}
		}, this );

		// Insert buttons.
		var buttonsHtml = [],
			buttons = CKEDITOR.dialog._.uiElementBuilders.hbox.build( this, {
				type: 'hbox',
				className: 'cke_dialog_footer_buttons',
				widths: [],
				children: definition.buttons
			}, buttonsHtml ).getChild();
		this.parts.footer.setHtml( buttonsHtml.join( '' ) );

		for ( i = 0; i < buttons.length; i++ )
			this._.buttons[ buttons[ i ].id ] = buttons[ i ];

		/**
		 * Current state of the dialog. Use the {@link #setState} method to update it.
		 * See the {@link #event-state} event to know more.
		 *
		 * @readonly
		 * @property {Number} [state=CKEDITOR.DIALOG_STATE_IDLE]
		 */
	};

	// Focusable interface. Use it via dialog.addFocusable.
	function Focusable( dialog, element, index ) {
		this.element = element;
		this.focusIndex = index;
		// TODO: support tabIndex for focusables.
		this.tabIndex = 0;
		this.isFocusable = function() {
			return !element.getAttribute( 'disabled' ) && element.isVisible();
		};
		this.focus = function() {
			dialog._.currentFocusIndex = this.focusIndex;
			this.element.focus();
		};
		// Bind events
		element.on( 'keydown', function( e ) {
			if ( e.data.getKeystroke() in { 32: 1, 13: 1 } )
				this.fire( 'click' );
		} );
		element.on( 'focus', function() {
			this.fire( 'mouseover' );
		} );
		element.on( 'blur', function() {
			this.fire( 'mouseout' );
		} );
	}

	// Re-layout the dialog on window resize.
	function resizeWithWindow( dialog ) {
		var win = CKEDITOR.document.getWindow();
		function resizeHandler() {
			dialog.layout();
		}
		win.on( 'resize', resizeHandler );
		dialog.on( 'hide', function() {
			win.removeListener( 'resize', resizeHandler );
		} );
	}

	CKEDITOR.dialog.prototype = {
		destroy: function() {
			this.hide();
			this._.element.remove();
		},

		/**
		 * Resizes the dialog.
		 *
		 *		dialogObj.resize( 800, 640 );
		 *
		 * @method
		 * @param {Number} width The width of the dialog in pixels.
		 * @param {Number} height The height of the dialog in pixels.
		 */
		resize: ( function() {
			return function( width, height ) {
				if ( this._.contentSize && this._.contentSize.width == width && this._.contentSize.height == height )
					return;

				CKEDITOR.dialog.fire( 'resize', {
					dialog: this,
					width: width,
					height: height
				}, this._.editor );

				this.fire( 'resize', {
					width: width,
					height: height
				}, this._.editor );

				var contents = this.parts.contents;
				contents.setStyles( {
					width: width + 'px',
					height: height + 'px'
				} );

				// Update dialog position when dimension get changed in RTL.
				if ( this._.editor.lang.dir == 'rtl' && this._.position )
					this._.position.x = CKEDITOR.document.getWindow().getViewPaneSize().width - this._.contentSize.width - parseInt( this._.element.getFirst().getStyle( 'right' ), 10 );

				this._.contentSize = { width: width, height: height };
			};
		} )(),

		/**
		 * Gets the current size of the dialog in pixels.
		 *
		 * var width = dialogObj.getSize().width;
		 *
		 * @returns {Object}
		 * @returns {Number} return.width
		 * @returns {Number} return.height
		 */
		getSize: function() {
			var element = this._.element.getFirst();
			return { width: element.$.offsetWidth || 0, height: element.$.offsetHeight || 0 };
		},

		/**
		 * Moves the dialog to an `(x, y)` coordinate relative to the window.
		 *
		 * dialogObj.move( 10, 40 );
		 *
		 * @method
		 * @param {Number} x The target x-coordinate.
		 * @param {Number} y The target y-coordinate.
		 * @param {Boolean} save Flag indicate whether the dialog position should be remembered on next open up.
		 */
		move: function( x, y, save ) {

			// The dialog may be fixed positioned or absolute positioned. Ask the
			// browser what is the current situation first.
			var element = this._.element.getFirst(), rtl = this._.editor.lang.dir == 'rtl';
			var isFixed = element.getComputedStyle( 'position' ) == 'fixed';

			// (https://dev.ckeditor.com/ticket/8888) In some cases of a very small viewport, dialog is incorrectly
			// positioned in IE7. It also happens that it remains sticky and user cannot
			// scroll down/up to reveal dialog's content below/above the viewport; this is
			// cumbersome.
			// The only way to fix this is to move mouse out of the browser and
			// go back to see that dialog position is automagically fixed. No events,
			// no style change - pure magic. This is a IE7 rendering issue, which can be
			// fixed with dummy style redraw on each move.
			if ( CKEDITOR.env.ie )
				element.setStyle( 'zoom', '100%' );

			if ( isFixed && this._.position && this._.position.x == x && this._.position.y == y )
				return;

			// Save the current position.
			this._.position = { x: x, y: y };

			// If not fixed positioned, add scroll position to the coordinates.
			if ( !isFixed ) {
				var scrollPosition = CKEDITOR.document.getWindow().getScrollPosition();
				x += scrollPosition.x;
				y += scrollPosition.y;
			}

			// Translate coordinate for RTL.
			if ( rtl ) {
				var dialogSize = this.getSize(), viewPaneSize = CKEDITOR.document.getWindow().getViewPaneSize();
				x = viewPaneSize.width - dialogSize.width - x;
			}

			var styles = { 'top': ( y > 0 ? y : 0 ) + 'px' };
			styles[ rtl ? 'right' : 'left' ] = ( x > 0 ? x : 0 ) + 'px';

			element.setStyles( styles );

			save && ( this._.moved = 1 );
		},

		/**
		 * Gets the dialog's position in the window.
		 *
		 *		var dialogX = dialogObj.getPosition().x;
		 *
		 * @returns {Object}
		 * @returns {Number} return.x
		 * @returns {Number} return.y
		 */
		getPosition: function() {
			return CKEDITOR.tools.extend( {}, this._.position );
		},

		/**
		 * Shows the dialog box.
		 *
		 *		dialogObj.show();
		 */
		show: function() {
			// Insert the dialog's element to the root document.
			var element = this._.element;
			var definition = this.definition;
			if ( !( element.getParent() && element.getParent().equals( CKEDITOR.document.getBody() ) ) )
				element.appendTo( CKEDITOR.document.getBody() );
			else
				element.setStyle( 'display', 'block' );

			// First, set the dialog to an appropriate size.
			this.resize(
				this._.contentSize && this._.contentSize.width || definition.width || definition.minWidth,
				this._.contentSize && this._.contentSize.height || definition.height || definition.minHeight
			);

			// Reset all inputs back to their default value.
			this.reset();

			// Selects the first tab if no tab is already selected.
			if ( this._.currentTabId === null ) {
				this.selectPage( this.definition.contents[ 0 ].id );
			}

			// Set z-index.
			if ( CKEDITOR.dialog._.currentZIndex === null )
				CKEDITOR.dialog._.currentZIndex = this._.editor.config.baseFloatZIndex;
			this._.element.getFirst().setStyle( 'z-index', CKEDITOR.dialog._.currentZIndex += 10 );

			// Maintain the dialog ordering and dialog cover.
			if ( CKEDITOR.dialog._.currentTop === null ) {
				CKEDITOR.dialog._.currentTop = this;
				this._.parentDialog = null;
				showCover( this._.editor );

			} else {
				this._.parentDialog = CKEDITOR.dialog._.currentTop;
				var parentElement = this._.parentDialog.getElement().getFirst();
				parentElement.$.style.zIndex -= Math.floor( this._.editor.config.baseFloatZIndex / 2 );
				CKEDITOR.dialog._.currentTop = this;
			}

			element.on( 'keydown', accessKeyDownHandler );
			element.on( 'keyup', accessKeyUpHandler );

			// Reset the hasFocus state.
			this._.hasFocus = false;

			for ( var i in definition.contents ) {
				if ( !definition.contents[ i ] )
					continue;

				var content = definition.contents[ i ],
					tab = this._.tabs[ content.id ],
					requiredContent = content.requiredContent,
					enableElements = 0;

				if ( !tab )
					continue;

				for ( var j in this._.contents[ content.id ] ) {
					var elem = this._.contents[ content.id ][ j ];

					if ( elem.type == 'hbox' || elem.type == 'vbox' || !elem.getInputElement() )
						continue;

					if ( elem.requiredContent && !this._.editor.activeFilter.check( elem.requiredContent ) )
						elem.disable();
					else {
						elem.enable();
						enableElements++;
					}
				}

				if ( !enableElements || ( requiredContent && !this._.editor.activeFilter.check( requiredContent ) ) )
					tab[ 0 ].addClass( 'cke_dialog_tab_disabled' );
				else
					tab[ 0 ].removeClass( 'cke_dialog_tab_disabled' );
			}

			CKEDITOR.tools.setTimeout( function() {
				this.layout();
				resizeWithWindow( this );

				this.parts.dialog.setStyle( 'visibility', '' );

				// Execute onLoad for the first show.
				this.fireOnce( 'load', {} );
				CKEDITOR.ui.fire( 'ready', this );

				this.fire( 'show', {} );
				this._.editor.fire( 'dialogShow', this );

				if ( !this._.parentDialog )
					this._.editor.focusManager.lock();

				// Save the initial values of the dialog.
				this.foreach( function( contentObj ) {
					contentObj.setInitValue && contentObj.setInitValue();
				} );

			}, 100, this );
		},

		/**
		 * Rearrange the dialog to its previous position or the middle of the window.
		 *
		 * @since 3.5
		 */
		layout: function() {
			var el = this.parts.dialog;
			var dialogSize = this.getSize();
			var win = CKEDITOR.document.getWindow(),
					viewSize = win.getViewPaneSize();

			var posX = ( viewSize.width - dialogSize.width ) / 2,
				posY = ( viewSize.height - dialogSize.height ) / 2;

			// Switch to absolute position when viewport is smaller than dialog size.
			if ( !CKEDITOR.env.ie6Compat ) {
				if ( dialogSize.height + ( posY > 0 ? posY : 0 ) > viewSize.height || dialogSize.width + ( posX > 0 ? posX : 0 ) > viewSize.width ) {
					el.setStyle( 'position', 'absolute' );
				} else {
					el.setStyle( 'position', 'fixed' );
				}
			}

			this.move( this._.moved ? this._.position.x : posX, this._.moved ? this._.position.y : posY );
		},

		/**
		 * Executes a function for each UI element.
		 *
		 * @param {Function} fn Function to execute for each UI element.
		 * @returns {CKEDITOR.dialog} The current dialog object.
		 */
		foreach: function( fn ) {
			for ( var i in this._.contents ) {
				for ( var j in this._.contents[ i ] ) {
					fn.call( this, this._.contents[i][j] );
				}
			}

			return this;
		},

		/**
		 * Resets all input values in the dialog.
		 *
		 *		dialogObj.reset();
		 *
		 * @method
		 * @chainable
		 */
		reset: ( function() {
			var fn = function( widget ) {
					if ( widget.reset )
						widget.reset( 1 );
				};
			return function() {
				this.foreach( fn );
				return this;
			};
		} )(),


		/**
		 * Calls the {@link CKEDITOR.dialog.definition.uiElement#setup} method of each
		 * of the UI elements, with the arguments passed through it.
		 * It is usually being called when the dialog is opened, to put the initial value inside the field.
		 *
		 *		dialogObj.setupContent();
		 *
		 *		var timestamp = ( new Date() ).valueOf();
		 *		dialogObj.setupContent( timestamp );
		 */
		setupContent: function() {
			var args = arguments;
			this.foreach( function( widget ) {
				if ( widget.setup )
					widget.setup.apply( widget, args );
			} );
		},

		/**
		 * Calls the {@link CKEDITOR.dialog.definition.uiElement#commit} method of each
		 * of the UI elements, with the arguments passed through it.
		 * It is usually being called when the user confirms the dialog, to process the values.
		 *
		 *		dialogObj.commitContent();
		 *
		 *		var timestamp = ( new Date() ).valueOf();
		 *		dialogObj.commitContent( timestamp );
		 */
		commitContent: function() {
			var args = arguments;
			this.foreach( function( widget ) {
				// Make sure IE triggers "change" event on last focused input before closing the dialog. (https://dev.ckeditor.com/ticket/7915)
				if ( CKEDITOR.env.ie && this._.currentFocusIndex == widget.focusIndex )
					widget.getInputElement().$.blur();

				if ( widget.commit )
					widget.commit.apply( widget, args );
			} );
		},

		/**
		 * Hides the dialog box.
		 *
		 *		dialogObj.hide();
		 */
		hide: function() {
			if ( !this.parts.dialog.isVisible() )
				return;

			this.fire( 'hide', {} );
			this._.editor.fire( 'dialogHide', this );
			// Reset the tab page.
			this.selectPage( this._.tabIdList[ 0 ] );
			var element = this._.element;
			element.setStyle( 'display', 'none' );
			this.parts.dialog.setStyle( 'visibility', 'hidden' );
			// Unregister all access keys associated with this dialog.
			unregisterAccessKey( this );

			// Close any child(top) dialogs first.
			while ( CKEDITOR.dialog._.currentTop != this )
				CKEDITOR.dialog._.currentTop.hide();

			// Maintain dialog ordering and remove cover if needed.
			if ( !this._.parentDialog )
				hideCover( this._.editor );
			else {
				var parentElement = this._.parentDialog.getElement().getFirst();
				parentElement.setStyle( 'z-index', parseInt( parentElement.$.style.zIndex, 10 ) + Math.floor( this._.editor.config.baseFloatZIndex / 2 ) );
			}
			CKEDITOR.dialog._.currentTop = this._.parentDialog;

			// Deduct or clear the z-index.
			if ( !this._.parentDialog ) {
				CKEDITOR.dialog._.currentZIndex = null;

				// Remove access key handlers.
				element.removeListener( 'keydown', accessKeyDownHandler );
				element.removeListener( 'keyup', accessKeyUpHandler );

				var editor = this._.editor;
				editor.focus();

				// Give a while before unlock, waiting for focus to return to the editable. (https://dev.ckeditor.com/ticket/172)
				setTimeout( function() {
					editor.focusManager.unlock();

					// Fixed iOS focus issue (https://dev.ckeditor.com/ticket/12381).
					// Keep in mind that editor.focus() does not work in this case.
					if ( CKEDITOR.env.iOS ) {
						editor.window.focus();
					}
				}, 0 );

			} else {
				CKEDITOR.dialog._.currentZIndex -= 10;
			}

			delete this._.parentDialog;
			// Reset the initial values of the dialog.
			this.foreach( function( contentObj ) {
				contentObj.resetInitValue && contentObj.resetInitValue();
			} );

			// Reset dialog state back to IDLE, if busy (https://dev.ckeditor.com/ticket/13213).
			this.setState( CKEDITOR.DIALOG_STATE_IDLE );
		},

		/**
		 * Adds a tabbed page into the dialog.
		 *
		 * @param {Object} contents Content definition.
		 */
		addPage: function( contents ) {
			if ( contents.requiredContent && !this._.editor.filter.check( contents.requiredContent ) )
				return;

			var pageHtml = [],
				titleHtml = contents.label ? ' title="' + CKEDITOR.tools.htmlEncode( contents.label ) + '"' : '',
				vbox = CKEDITOR.dialog._.uiElementBuilders.vbox.build( this, {
					type: 'vbox',
					className: 'cke_dialog_page_contents',
					children: contents.elements,
					expand: !!contents.expand,
					padding: contents.padding,
					style: contents.style || 'width: 100%;'
				}, pageHtml );

			var contentMap = this._.contents[ contents.id ] = {},
				cursor,
				children = vbox.getChild(),
				enabledFields = 0;

			while ( ( cursor = children.shift() ) ) {
				// Count all allowed fields.
				if ( !cursor.notAllowed && cursor.type != 'hbox' && cursor.type != 'vbox' )
					enabledFields++;

				contentMap[ cursor.id ] = cursor;
				if ( typeof cursor.getChild == 'function' )
					children.push.apply( children, cursor.getChild() );
			}

			// If all fields are disabled (because they are not allowed) hide this tab.
			if ( !enabledFields )
				contents.hidden = true;

			// Create the HTML for the tab and the content block.
			var page = CKEDITOR.dom.element.createFromHtml( pageHtml.join( '' ) );
			page.setAttribute( 'role', 'tabpanel' );

			var env = CKEDITOR.env;
			var tabId = 'cke_' + contents.id + '_' + CKEDITOR.tools.getNextNumber(),
				tab = CKEDITOR.dom.element.createFromHtml( [
					'<a class="cke_dialog_tab"',
					( this._.pageCount > 0 ? ' cke_last' : 'cke_first' ),
					titleHtml,
					( !!contents.hidden ? ' style="display:none"' : '' ),
					' id="', tabId, '"',
					env.gecko && !env.hc ? '' : ' href="javascript:void(0)"',
					' tabIndex="-1"',
					' hidefocus="true"',
					' role="tab">',
					contents.label,
					'</a>'
				].join( '' ) );

			page.setAttribute( 'aria-labelledby', tabId );

			// Take records for the tabs and elements created.
			this._.tabs[ contents.id ] = [ tab, page ];
			this._.tabIdList.push( contents.id );
			!contents.hidden && this._.pageCount++;
			this._.lastTab = tab;
			this.updateStyle();

			// Attach the DOM nodes.

			page.setAttribute( 'name', contents.id );
			page.appendTo( this.parts.contents );

			tab.unselectable();
			this.parts.tabs.append( tab );

			// Add access key handlers if access key is defined.
			if ( contents.accessKey ) {
				registerAccessKey( this, this, 'CTRL+' + contents.accessKey, tabAccessKeyDown, tabAccessKeyUp );
				this._.accessKeyMap[ 'CTRL+' + contents.accessKey ] = contents.id;
			}
		},

		/**
		 * Activates a tab page in the dialog by its id.
		 *
		 *		dialogObj.selectPage( 'tab_1' );
		 *
		 * @param {String} id The id of the dialog tab to be activated.
		 */
		selectPage: function( id ) {
			if ( this._.currentTabId == id )
				return;

			if ( this._.tabs[ id ][ 0 ].hasClass( 'cke_dialog_tab_disabled' ) )
				return;

			// If event was canceled - do nothing.
			if ( this.fire( 'selectPage', { page: id, currentPage: this._.currentTabId } ) === false )
				return;

			// Hide the non-selected tabs and pages.
			for ( var i in this._.tabs ) {
				var tab = this._.tabs[ i ][ 0 ],
					page = this._.tabs[ i ][ 1 ];
				if ( i != id ) {
					tab.removeClass( 'cke_dialog_tab_selected' );
					page.hide();
				}
				page.setAttribute( 'aria-hidden', i != id );
			}

			var selected = this._.tabs[ id ];
			selected[ 0 ].addClass( 'cke_dialog_tab_selected' );

			// [IE] an invisible input[type='text'] will enlarge it's width
			// if it's value is long when it shows, so we clear it's value
			// before it shows and then recover it (https://dev.ckeditor.com/ticket/5649)
			if ( CKEDITOR.env.ie6Compat || CKEDITOR.env.ie7Compat ) {
				clearOrRecoverTextInputValue( selected[ 1 ] );
				selected[ 1 ].show();
				setTimeout( function() {
					clearOrRecoverTextInputValue( selected[ 1 ], 1 );
				}, 0 );
			} else {
				selected[ 1 ].show();
			}

			this._.currentTabId = id;
			this._.currentTabIndex = CKEDITOR.tools.indexOf( this._.tabIdList, id );
		},

		/**
		 * Dialog state-specific style updates.
		 */
		updateStyle: function() {
			// If only a single page shown, a different style is used in the central pane.
			this.parts.dialog[ ( this._.pageCount === 1 ? 'add' : 'remove' ) + 'Class' ]( 'cke_single_page' );
		},

		/**
		 * Hides a page's tab away from the dialog.
		 *
		 *		dialog.hidePage( 'tab_3' );
		 *
		 * @param {String} id The page's Id.
		 */
		hidePage: function( id ) {
			var tab = this._.tabs[ id ] && this._.tabs[ id ][ 0 ];
			if ( !tab || this._.pageCount == 1 || !tab.isVisible() )
				return;
			// Switch to other tab first when we're hiding the active tab.
			else if ( id == this._.currentTabId )
				this.selectPage( getPreviousVisibleTab.call( this ) );

			tab.hide();
			this._.pageCount--;
			this.updateStyle();
		},

		/**
		 * Unhides a page's tab.
		 *
		 *		dialog.showPage( 'tab_2' );
		 *
		 * @param {String} id The page's Id.
		 */
		showPage: function( id ) {
			var tab = this._.tabs[ id ] && this._.tabs[ id ][ 0 ];
			if ( !tab )
				return;
			tab.show();
			this._.pageCount++;
			this.updateStyle();
		},

		/**
		 * Gets the root DOM element of the dialog.
		 *
		 *		var dialogElement = dialogObj.getElement().getFirst();
		 *		dialogElement.setStyle( 'padding', '5px' );
		 *
		 * @returns {CKEDITOR.dom.element} The `<span>` element containing this dialog.
		 */
		getElement: function() {
			return this._.element;
		},

		/**
		 * Gets the name of the dialog.
		 *
		 *		var dialogName = dialogObj.getName();
		 *
		 * @returns {String} The name of this dialog.
		 */
		getName: function() {
			return this._.name;
		},

		/**
		 * Gets a dialog UI element object from a dialog page.
		 *
		 *		dialogObj.getContentElement( 'tabId', 'elementId' ).setValue( 'Example' );
		 *
		 * @param {String} pageId id of dialog page.
		 * @param {String} elementId id of UI element.
		 * @returns {CKEDITOR.ui.dialog.uiElement} The dialog UI element.
		 */
		getContentElement: function( pageId, elementId ) {
			var page = this._.contents[ pageId ];
			return page && page[ elementId ];
		},

		/**
		 * Gets the value of a dialog UI element.
		 *
		 *		alert( dialogObj.getValueOf( 'tabId', 'elementId' ) );
		 *
		 * @param {String} pageId id of dialog page.
		 * @param {String} elementId id of UI element.
		 * @returns {Object} The value of the UI element.
		 */
		getValueOf: function( pageId, elementId ) {
			return this.getContentElement( pageId, elementId ).getValue();
		},

		/**
		 * Sets the value of a dialog UI element.
		 *
		 *		dialogObj.setValueOf( 'tabId', 'elementId', 'Example' );
		 *
		 * @param {String} pageId id of the dialog page.
		 * @param {String} elementId id of the UI element.
		 * @param {Object} value The new value of the UI element.
		 */
		setValueOf: function( pageId, elementId, value ) {
			return this.getContentElement( pageId, elementId ).setValue( value );
		},

		/**
		 * Gets the UI element of a button in the dialog's button row.
		 *
		 *		@returns {CKEDITOR.ui.dialog.button} The button object.
		 *
		 * @param {String} id The id of the button.
		 */
		getButton: function( id ) {
			return this._.buttons[ id ];
		},

		/**
		 * Simulates a click to a dialog button in the dialog's button row.
		 *
		 * @returns The return value of the dialog's `click` event.
		 *
		 * @param {String} id The id of the button.
		 */
		click: function( id ) {
			return this._.buttons[ id ].click();
		},

		/**
		 * Disables a dialog button.
		 *
		 * @param {String} id The id of the button.
		 */
		disableButton: function( id ) {
			return this._.buttons[ id ].disable();
		},

		/**
		 * Enables a dialog button.
		 *
		 * @param {String} id The id of the button.
		 */
		enableButton: function( id ) {
			return this._.buttons[ id ].enable();
		},

		/**
		 * Gets the number of pages in the dialog.
		 *
		 * @returns {Number} Page count.
		 */
		getPageCount: function() {
			return this._.pageCount;
		},

		/**
		 * Gets the editor instance which opened this dialog.
		 *
		 * @returns {CKEDITOR.editor} Parent editor instances.
		 */
		getParentEditor: function() {
			return this._.editor;
		},

		/**
		 * Gets the element that was selected when opening the dialog, if any.
		 *
		 * @returns {CKEDITOR.dom.element} The element that was selected, or `null`.
		 */
		getSelectedElement: function() {
			return this.getParentEditor().getSelection().getSelectedElement();
		},

		/**
		 * Adds element to dialog's focusable list.
		 *
		 * @param {CKEDITOR.dom.element} element
		 * @param {Number} [index]
		 */
		addFocusable: function( element, index ) {
			if ( typeof index == 'undefined' ) {
				index = this._.focusList.length;
				this._.focusList.push( new Focusable( this, element, index ) );
			} else {
				this._.focusList.splice( index, 0, new Focusable( this, element, index ) );
				for ( var i = index + 1; i < this._.focusList.length; i++ )
					this._.focusList[ i ].focusIndex++;
			}
		},

		/**
		 * Sets the dialog {@link #property-state}.
		 *
		 * @since 4.5
		 * @param {Number} state Either {@link CKEDITOR#DIALOG_STATE_IDLE} or {@link CKEDITOR#DIALOG_STATE_BUSY}.
		 */
		setState: function( state ) {
			var oldState = this.state;

			if ( oldState == state ) {
				return;
			}

			this.state = state;

			if ( state == CKEDITOR.DIALOG_STATE_BUSY ) {
				// Insert the spinner on demand.
				if ( !this.parts.spinner ) {
					var dir = this.getParentEditor().lang.dir,
						spinnerDef = {
							attributes: {
								'class': 'cke_dialog_spinner'
							},
							styles: {
								'float': dir == 'rtl' ? 'right' : 'left'
							}
						};

					spinnerDef.styles[ 'margin-' + ( dir == 'rtl' ? 'left' : 'right' ) ] = '8px';

					this.parts.spinner = CKEDITOR.document.createElement( 'div', spinnerDef );

					this.parts.spinner.setHtml( '&#8987;' );
					this.parts.spinner.appendTo( this.parts.title, 1 );
				}

				// Finally, show the spinner.
				this.parts.spinner.show();

				this.getButton( 'ok' ).disable();
			} else if ( state == CKEDITOR.DIALOG_STATE_IDLE ) {
				// Hide the spinner. But don't do anything if there is no spinner yet.
				this.parts.spinner && this.parts.spinner.hide();

				this.getButton( 'ok' ).enable();
			}

			this.fire( 'state', state );
		}
	};

	CKEDITOR.tools.extend( CKEDITOR.dialog, {
		/**
		 * Registers a dialog.
		 *
		 *		// Full sample plugin, which does not only register a dialog window but also adds an item to the context menu.
		 *		// To open the dialog window, choose "Open dialog" in the context menu.
		 *		CKEDITOR.plugins.add( 'myplugin', {
		 *			init: function( editor ) {
		 *				editor.addCommand( 'mydialog',new CKEDITOR.dialogCommand( 'mydialog' ) );
		 *
		 *				if ( editor.contextMenu ) {
		 *					editor.addMenuGroup( 'mygroup', 10 );
		 *					editor.addMenuItem( 'My Dialog', {
		 *						label: 'Open dialog',
		 *						command: 'mydialog',
		 *						group: 'mygroup'
		 *					} );
		 *					editor.contextMenu.addListener( function( element ) {
		 *						return { 'My Dialog': CKEDITOR.TRISTATE_OFF };
		 *					} );
		 *				}
		 *
		 *				CKEDITOR.dialog.add( 'mydialog', function( api ) {
		 *					// CKEDITOR.dialog.definition
		 *					var dialogDefinition = {
		 *						title: 'Sample dialog',
		 *						minWidth: 390,
		 *						minHeight: 130,
		 *						contents: [
		 *							{
		 *								id: 'tab1',
		 *								label: 'Label',
		 *								title: 'Title',
		 *								expand: true,
		 *								padding: 0,
		 *								elements: [
		 *									{
		 *										type: 'html',
		 *										html: '<p>This is some sample HTML content.</p>'
		 *									},
		 *									{
		 *										type: 'textarea',
		 *										id: 'textareaId',
		 *										rows: 4,
		 *										cols: 40
		 *									}
		 *								]
		 *							}
		 *						],
		 *						buttons: [ CKEDITOR.dialog.okButton, CKEDITOR.dialog.cancelButton ],
		 *						onOk: function() {
		 *							// "this" is now a CKEDITOR.dialog object.
		 *							// Accessing dialog elements:
		 *							var textareaObj = this.getContentElement( 'tab1', 'textareaId' );
		 *							alert( "You have entered: " + textareaObj.getValue() );
		 *						}
		 *					};
		 *
		 *					return dialogDefinition;
		 *				} );
		 *			}
		 *		} );
		 *
		 *		CKEDITOR.replace( 'editor1', { extraPlugins: 'myplugin' } );
		 *
		 * @static
		 * @param {String} name The dialog's name.
		 * @param {Function/String} dialogDefinition
		 * A function returning the dialog's definition, or the URL to the `.js` file holding the function.
		 * The function should accept an argument `editor` which is the current editor instance, and
		 * return an object conforming to {@link CKEDITOR.dialog.definition}.
		 * @see CKEDITOR.dialog.definition
		 */
		add: function( name, dialogDefinition ) {
			// Avoid path registration from multiple instances override definition.
			if ( !this._.dialogDefinitions[ name ] || typeof dialogDefinition == 'function' )
				this._.dialogDefinitions[ name ] = dialogDefinition;
		},

		/**
		 * @static
		 * @todo
		 */
		exists: function( name ) {
			return !!this._.dialogDefinitions[ name ];
		},

		/**
		 * @static
		 * @todo
		 */
		getCurrent: function() {
			return CKEDITOR.dialog._.currentTop;
		},

		/**
		 * Check whether tab wasn't removed by {@link CKEDITOR.config#removeDialogTabs}.
		 *
		 * @since 4.1
		 * @static
		 * @param {CKEDITOR.editor} editor
		 * @param {String} dialogName
		 * @param {String} tabName
		 * @returns {Boolean}
		 */
		isTabEnabled: function( editor, dialogName, tabName ) {
			var cfg = editor.config.removeDialogTabs;

			return !( cfg && cfg.match( new RegExp( '(?:^|;)' + dialogName + ':' + tabName + '(?:$|;)', 'i' ) ) );
		},

		/**
		 * The default OK button for dialogs. Fires the `ok` event and closes the dialog if the event succeeds.
		 *
		 * @static
		 * @method
		 */
		okButton: ( function() {
			var retval = function( editor, override ) {
					override = override || {};
					return CKEDITOR.tools.extend( {
						id: 'ok',
						type: 'button',
						label: editor.lang.common.ok,
						'class': 'cke_dialog_ui_button_ok',
						onClick: function( evt ) {
							var dialog = evt.data.dialog;
							if ( dialog.fire( 'ok', { hide: true } ).hide !== false )
								dialog.hide();
						}
					}, override, true );
				};
			retval.type = 'button';
			retval.override = function( override ) {
				return CKEDITOR.tools.extend( function( editor ) {
					return retval( editor, override );
				}, { type: 'button' }, true );
			};
			return retval;
		} )(),

		/**
		 * The default cancel button for dialogs. Fires the `cancel` event and
		 * closes the dialog if no UI element value changed.
		 *
		 * @static
		 * @method
		 */
		cancelButton: ( function() {
			var retval = function( editor, override ) {
					override = override || {};
					return CKEDITOR.tools.extend( {
						id: 'cancel',
						type: 'button',
						label: editor.lang.common.cancel,
						'class': 'cke_dialog_ui_button_cancel',
						onClick: function( evt ) {
							var dialog = evt.data.dialog;
							if ( dialog.fire( 'cancel', { hide: true } ).hide !== false )
								dialog.hide();
						}
					}, override, true );
				};
			retval.type = 'button';
			retval.override = function( override ) {
				return CKEDITOR.tools.extend( function( editor ) {
					return retval( editor, override );
				}, { type: 'button' }, true );
			};
			return retval;
		} )(),

		/**
		 * Registers a dialog UI element.
		 *
		 * @static
		 * @param {String} typeName The name of the UI element.
		 * @param {Function} builder The function to build the UI element.
		 */
		addUIElement: function( typeName, builder ) {
			this._.uiElementBuilders[ typeName ] = builder;
		}
	} );

	CKEDITOR.dialog._ = {
		uiElementBuilders: {},

		dialogDefinitions: {},

		currentTop: null,

		currentZIndex: null
	};

	// "Inherit" (copy actually) from CKEDITOR.event.
	CKEDITOR.event.implementOn( CKEDITOR.dialog );
	CKEDITOR.event.implementOn( CKEDITOR.dialog.prototype );

	var defaultDialogDefinition = {
		resizable: CKEDITOR.DIALOG_RESIZE_BOTH,
		minWidth: 600,
		minHeight: 400,
		buttons: [ CKEDITOR.dialog.okButton, CKEDITOR.dialog.cancelButton ]
	};

	// Tool function used to return an item from an array based on its id
	// property.
	var getById = function( array, id, recurse ) {
			for ( var i = 0, item;
			( item = array[ i ] ); i++ ) {
				if ( item.id == id )
					return item;
				if ( recurse && item[ recurse ] ) {
					var retval = getById( item[ recurse ], id, recurse );
					if ( retval )
						return retval;
				}
			}
			return null;
		};

	// Tool function used to add an item into an array.
	var addById = function( array, newItem, nextSiblingId, recurse, nullIfNotFound ) {
			if ( nextSiblingId ) {
				for ( var i = 0, item;
				( item = array[ i ] ); i++ ) {
					if ( item.id == nextSiblingId ) {
						array.splice( i, 0, newItem );
						return newItem;
					}

					if ( recurse && item[ recurse ] ) {
						var retval = addById( item[ recurse ], newItem, nextSiblingId, recurse, true );
						if ( retval )
							return retval;
					}
				}

				if ( nullIfNotFound )
					return null;
			}

			array.push( newItem );
			return newItem;
		};

	// Tool function used to remove an item from an array based on its id.
	var removeById = function( array, id, recurse ) {
			for ( var i = 0, item;
			( item = array[ i ] ); i++ ) {
				if ( item.id == id )
					return array.splice( i, 1 );
				if ( recurse && item[ recurse ] ) {
					var retval = removeById( item[ recurse ], id, recurse );
					if ( retval )
						return retval;
				}
			}
			return null;
		};

	/**
	 * This class is not really part of the API. It is the `definition` property value
	 * passed to `dialogDefinition` event handlers.
	 *
	 *		CKEDITOR.on( 'dialogDefinition', function( evt ) {
	 *			var definition = evt.data.definition;
	 *			var content = definition.getContents( 'page1' );
	 * 			// ...
	 *		} );
	 *
	 * @private
	 * @class CKEDITOR.dialog.definitionObject
	 * @extends CKEDITOR.dialog.definition
	 * @constructor Creates a definitionObject class instance.
	 */
	var definitionObject = function( dialog, dialogDefinition ) {
			// TODO : Check if needed.
			this.dialog = dialog;

			// Transform the contents entries in contentObjects.
			var contents = dialogDefinition.contents;
			for ( var i = 0, content;
			( content = contents[ i ] ); i++ )
				contents[ i ] = content && new contentObject( dialog, content );

			CKEDITOR.tools.extend( this, dialogDefinition );
		};

	definitionObject.prototype = {
		/**
		 * Gets a content definition.
		 *
		 * @param {String} id The id of the content definition.
		 * @returns {CKEDITOR.dialog.definition.content} The content definition matching id.
		 */
		getContents: function( id ) {
			return getById( this.contents, id );
		},

		/**
		 * Gets a button definition.
		 *
		 * @param {String} id The id of the button definition.
		 * @returns {CKEDITOR.dialog.definition.button} The button definition matching id.
		 */
		getButton: function( id ) {
			return getById( this.buttons, id );
		},

		/**
		 * Adds a content definition object under this dialog definition.
		 *
		 * @param {CKEDITOR.dialog.definition.content} contentDefinition The
		 * content definition.
		 * @param {String} [nextSiblingId] The id of an existing content
		 * definition which the new content definition will be inserted
		 * before. Omit if the new content definition is to be inserted as
		 * the last item.
		 * @returns {CKEDITOR.dialog.definition.content} The inserted content definition.
		 */
		addContents: function( contentDefinition, nextSiblingId ) {
			return addById( this.contents, contentDefinition, nextSiblingId );
		},

		/**
		 * Adds a button definition object under this dialog definition.
		 *
		 * @param {CKEDITOR.dialog.definition.button} buttonDefinition The
		 * button definition.
		 * @param {String} [nextSiblingId] The id of an existing button
		 * definition which the new button definition will be inserted
		 * before. Omit if the new button definition is to be inserted as
		 * the last item.
		 * @returns {CKEDITOR.dialog.definition.button} The inserted button definition.
		 */
		addButton: function( buttonDefinition, nextSiblingId ) {
			return addById( this.buttons, buttonDefinition, nextSiblingId );
		},

		/**
		 * Removes a content definition from this dialog definition.
		 *
		 * @param {String} id The id of the content definition to be removed.
		 * @returns {CKEDITOR.dialog.definition.content} The removed content definition.
		 */
		removeContents: function( id ) {
			removeById( this.contents, id );
		},

		/**
		 * Removes a button definition from the dialog definition.
		 *
		 * @param {String} id The id of the button definition to be removed.
		 * @returns {CKEDITOR.dialog.definition.button} The removed button definition.
		 */
		removeButton: function( id ) {
			removeById( this.buttons, id );
		}
	};

	/**
	 * This class is not really part of the API. It is the template of the
	 * objects representing content pages inside the
	 * CKEDITOR.dialog.definitionObject.
	 *
	 *		CKEDITOR.on( 'dialogDefinition', function( evt ) {
	 *			var definition = evt.data.definition;
	 *			var content = definition.getContents( 'page1' );
	 *			content.remove( 'textInput1' );
	 *			// ...
	 *		} );
	 *
	 * @private
	 * @class CKEDITOR.dialog.definition.contentObject
	 * @constructor Creates a contentObject class instance.
	 */
	function contentObject( dialog, contentDefinition ) {
		this._ = {
			dialog: dialog
		};

		CKEDITOR.tools.extend( this, contentDefinition );
	}

	contentObject.prototype = {
		/**
		 * Gets a UI element definition under the content definition.
		 *
		 * @param {String} id The id of the UI element definition.
		 * @returns {CKEDITOR.dialog.definition.uiElement}
		 */
		get: function( id ) {
			return getById( this.elements, id, 'children' );
		},

		/**
		 * Adds a UI element definition to the content definition.
		 *
		 * @param {CKEDITOR.dialog.definition.uiElement} elementDefinition The
		 * UI elemnet definition to be added.
		 * @param {String} nextSiblingId The id of an existing UI element
		 * definition which the new UI element definition will be inserted
		 * before. Omit if the new button definition is to be inserted as
		 * the last item.
		 * @returns {CKEDITOR.dialog.definition.uiElement} The element definition inserted.
		 */
		add: function( elementDefinition, nextSiblingId ) {
			return addById( this.elements, elementDefinition, nextSiblingId, 'children' );
		},

		/**
		 * Removes a UI element definition from the content definition.
		 *
		 * @param {String} id The id of the UI element definition to be removed.
		 * @returns {CKEDITOR.dialog.definition.uiElement} The element definition removed.
		 */
		remove: function( id ) {
			removeById( this.elements, id, 'children' );
		}
	};

	function initDragAndDrop( dialog ) {
		var lastCoords = null,
			abstractDialogCoords = null,
			editor = dialog.getParentEditor(),
			magnetDistance = editor.config.dialog_magnetDistance,
			margins = CKEDITOR.skin.margins || [ 0, 0, 0, 0 ];

		if ( typeof magnetDistance == 'undefined' )
			magnetDistance = 20;

		function mouseMoveHandler( evt ) {
			var dialogSize = dialog.getSize(),
				viewPaneSize = CKEDITOR.document.getWindow().getViewPaneSize(),
				x = evt.data.$.screenX,
				y = evt.data.$.screenY,
				dx = x - lastCoords.x,
				dy = y - lastCoords.y,
				realX, realY;

			lastCoords = { x: x, y: y };
			abstractDialogCoords.x += dx;
			abstractDialogCoords.y += dy;

			if ( abstractDialogCoords.x + margins[ 3 ] < magnetDistance )
				realX = -margins[ 3 ];
			else if ( abstractDialogCoords.x - margins[ 1 ] > viewPaneSize.width - dialogSize.width - magnetDistance )
				realX = viewPaneSize.width - dialogSize.width + ( editor.lang.dir == 'rtl' ? 0 : margins[ 1 ] );
			else
				realX = abstractDialogCoords.x;

			if ( abstractDialogCoords.y + margins[ 0 ] < magnetDistance )
				realY = -margins[ 0 ];
			else if ( abstractDialogCoords.y - margins[ 2 ] > viewPaneSize.height - dialogSize.height - magnetDistance )
				realY = viewPaneSize.height - dialogSize.height + margins[ 2 ];
			else
				realY = abstractDialogCoords.y;

			dialog.move( realX, realY, 1 );

			evt.data.preventDefault();
		}

		function mouseUpHandler() {
			CKEDITOR.document.removeListener( 'mousemove', mouseMoveHandler );
			CKEDITOR.document.removeListener( 'mouseup', mouseUpHandler );

			if ( CKEDITOR.env.ie6Compat ) {
				var coverDoc = currentCover.getChild( 0 ).getFrameDocument();
				coverDoc.removeListener( 'mousemove', mouseMoveHandler );
				coverDoc.removeListener( 'mouseup', mouseUpHandler );
			}
		}

		dialog.parts.title.on( 'mousedown', function( evt ) {
			lastCoords = { x: evt.data.$.screenX, y: evt.data.$.screenY };

			CKEDITOR.document.on( 'mousemove', mouseMoveHandler );
			CKEDITOR.document.on( 'mouseup', mouseUpHandler );
			abstractDialogCoords = dialog.getPosition();

			if ( CKEDITOR.env.ie6Compat ) {
				var coverDoc = currentCover.getChild( 0 ).getFrameDocument();
				coverDoc.on( 'mousemove', mouseMoveHandler );
				coverDoc.on( 'mouseup', mouseUpHandler );
			}

			evt.data.preventDefault();
		}, dialog );
	}

	function initResizeHandles( dialog ) {
		var def = dialog.definition,
			resizable = def.resizable;

		if ( resizable == CKEDITOR.DIALOG_RESIZE_NONE )
			return;

		var editor = dialog.getParentEditor();
		var wrapperWidth, wrapperHeight, viewSize, origin, startSize, dialogCover;

		var mouseDownFn = CKEDITOR.tools.addFunction( function( $event ) {
			startSize = dialog.getSize();

			var content = dialog.parts.contents,
				iframeDialog = content.$.getElementsByTagName( 'iframe' ).length;

			// Shim to help capturing "mousemove" over iframe.
			if ( iframeDialog ) {
				dialogCover = CKEDITOR.dom.element.createFromHtml( '<div class="cke_dialog_resize_cover" style="height: 100%; position: absolute; width: 100%;"></div>' );
				content.append( dialogCover );
			}

			// Calculate the offset between content and chrome size.
			wrapperHeight = startSize.height - dialog.parts.contents.getSize( 'height', !( CKEDITOR.env.gecko || CKEDITOR.env.ie && CKEDITOR.env.quirks ) );
			wrapperWidth = startSize.width - dialog.parts.contents.getSize( 'width', 1 );

			origin = { x: $event.screenX, y: $event.screenY };

			viewSize = CKEDITOR.document.getWindow().getViewPaneSize();

			CKEDITOR.document.on( 'mousemove', mouseMoveHandler );
			CKEDITOR.document.on( 'mouseup', mouseUpHandler );

			if ( CKEDITOR.env.ie6Compat ) {
				var coverDoc = currentCover.getChild( 0 ).getFrameDocument();
				coverDoc.on( 'mousemove', mouseMoveHandler );
				coverDoc.on( 'mouseup', mouseUpHandler );
			}

			$event.preventDefault && $event.preventDefault();
		} );

		// Prepend the grip to the dialog.
		dialog.on( 'load', function() {
			var direction = '';
			if ( resizable == CKEDITOR.DIALOG_RESIZE_WIDTH )
				direction = ' cke_resizer_horizontal';
			else if ( resizable == CKEDITOR.DIALOG_RESIZE_HEIGHT )
				direction = ' cke_resizer_vertical';
			var resizer = CKEDITOR.dom.element.createFromHtml(
				'<div' +
				' class="cke_resizer' + direction + ' cke_resizer_' + editor.lang.dir + '"' +
				' title="' + CKEDITOR.tools.htmlEncode( editor.lang.common.resize ) + '"' +
				' onmousedown="CKEDITOR.tools.callFunction(' + mouseDownFn + ', event )">' +
				// BLACK LOWER RIGHT TRIANGLE (ltr)
				// BLACK LOWER LEFT TRIANGLE (rtl)
				( editor.lang.dir == 'ltr' ? '\u25E2' : '\u25E3' ) +
				'</div>' );
			dialog.parts.footer.append( resizer, 1 );
		} );
		editor.on( 'destroy', function() {
			CKEDITOR.tools.removeFunction( mouseDownFn );
		} );

		function mouseMoveHandler( evt ) {
			var rtl = editor.lang.dir == 'rtl',
				dx = ( evt.data.$.screenX - origin.x ) * ( rtl ? -1 : 1 ),
				dy = evt.data.$.screenY - origin.y,
				width = startSize.width,
				height = startSize.height,
				internalWidth = width + dx * ( dialog._.moved ? 1 : 2 ),
				internalHeight = height + dy * ( dialog._.moved ? 1 : 2 ),
				element = dialog._.element.getFirst(),
				right = rtl && element.getComputedStyle( 'right' ),
				position = dialog.getPosition();

			if ( position.y + internalHeight > viewSize.height )
				internalHeight = viewSize.height - position.y;

			if ( ( rtl ? right : position.x ) + internalWidth > viewSize.width )
				internalWidth = viewSize.width - ( rtl ? right : position.x );

			// Make sure the dialog will not be resized to the wrong side when it's in the leftmost position for RTL.
			if ( ( resizable == CKEDITOR.DIALOG_RESIZE_WIDTH || resizable == CKEDITOR.DIALOG_RESIZE_BOTH ) )
				width = Math.max( def.minWidth || 0, internalWidth - wrapperWidth );

			if ( resizable == CKEDITOR.DIALOG_RESIZE_HEIGHT || resizable == CKEDITOR.DIALOG_RESIZE_BOTH )
				height = Math.max( def.minHeight || 0, internalHeight - wrapperHeight );

			dialog.resize( width, height );

			if ( !dialog._.moved )
				dialog.layout();

			evt.data.preventDefault();
		}

		function mouseUpHandler() {
			CKEDITOR.document.removeListener( 'mouseup', mouseUpHandler );
			CKEDITOR.document.removeListener( 'mousemove', mouseMoveHandler );

			if ( dialogCover ) {
				dialogCover.remove();
				dialogCover = null;
			}

			if ( CKEDITOR.env.ie6Compat ) {
				var coverDoc = currentCover.getChild( 0 ).getFrameDocument();
				coverDoc.removeListener( 'mouseup', mouseUpHandler );
				coverDoc.removeListener( 'mousemove', mouseMoveHandler );
			}
		}
	}

	var resizeCover;
	// Caching resuable covers and allowing only one cover
	// on screen.
	var covers = {},
		currentCover;

	function cancelEvent( ev ) {
		ev.data.preventDefault( 1 );
	}

	function showCover( editor ) {
		var win = CKEDITOR.document.getWindow(),
			config = editor.config,
			skinName = ( CKEDITOR.skinName || editor.config.skin ),
			backgroundColorStyle = config.dialog_backgroundCoverColor || ( skinName == 'moono-lisa' ? 'black' : 'white' ),
			backgroundCoverOpacity = config.dialog_backgroundCoverOpacity,
			baseFloatZIndex = config.baseFloatZIndex,
			coverKey = CKEDITOR.tools.genKey( backgroundColorStyle, backgroundCoverOpacity, baseFloatZIndex ),
			coverElement = covers[ coverKey ];

		if ( !coverElement ) {
			var html = [
				'<div tabIndex="-1" style="position: ', ( CKEDITOR.env.ie6Compat ? 'absolute' : 'fixed' ),
				'; z-index: ', baseFloatZIndex,
				'; top: 0px; left: 0px; ',
				( !CKEDITOR.env.ie6Compat ? 'background-color: ' + backgroundColorStyle : '' ),
				'" class="cke_dialog_background_cover">'
			];

			if ( CKEDITOR.env.ie6Compat ) {
				// Support for custom document.domain in IE.
				var iframeHtml = '<html><body style=\\\'background-color:' + backgroundColorStyle + ';\\\'></body></html>';

				html.push( '<iframe' +
					' hidefocus="true"' +
					' frameborder="0"' +
					' id="cke_dialog_background_iframe"' +
					' src="javascript:' );

				html.push( 'void((function(){' + encodeURIComponent(
					'document.open();' +
					// Support for custom document.domain in IE.
					'(' + CKEDITOR.tools.fixDomain + ')();' +
					'document.write( \'' + iframeHtml + '\' );' +
					'document.close();'
				) + '})())' );

				html.push( '"' +
					' style="' +
						'position:absolute;' +
						'left:0;' +
						'top:0;' +
						'width:100%;' +
						'height: 100%;' +
						'filter: progid:DXImageTransform.Microsoft.Alpha(opacity=0)">' +
					'</iframe>' );
			}

			html.push( '</div>' );

			coverElement = CKEDITOR.dom.element.createFromHtml( html.join( '' ) );
			coverElement.setOpacity( backgroundCoverOpacity !== undefined ? backgroundCoverOpacity : 0.5 );

			coverElement.on( 'keydown', cancelEvent );
			coverElement.on( 'keypress', cancelEvent );
			coverElement.on( 'keyup', cancelEvent );

			coverElement.appendTo( CKEDITOR.document.getBody() );
			covers[ coverKey ] = coverElement;
		} else {
			coverElement.show();
		}

		// Makes the dialog cover a focus holder as well.
		editor.focusManager.add( coverElement );

		currentCover = coverElement;
		var resizeFunc = function() {
				var size = win.getViewPaneSize();
				coverElement.setStyles( {
					width: size.width + 'px',
					height: size.height + 'px'
				} );
			};

		var scrollFunc = function() {
				var pos = win.getScrollPosition(),
					cursor = CKEDITOR.dialog._.currentTop;
				coverElement.setStyles( {
					left: pos.x + 'px',
					top: pos.y + 'px'
				} );

				if ( cursor ) {
					do {
						var dialogPos = cursor.getPosition();
						cursor.move( dialogPos.x, dialogPos.y );
					} while ( ( cursor = cursor._.parentDialog ) );
				}
			};

		resizeCover = resizeFunc;
		win.on( 'resize', resizeFunc );
		resizeFunc();
		// Using Safari/Mac, focus must be kept where it is (https://dev.ckeditor.com/ticket/7027)
		if ( !( CKEDITOR.env.mac && CKEDITOR.env.webkit ) )
			coverElement.focus();

		if ( CKEDITOR.env.ie6Compat ) {
			// IE BUG: win.$.onscroll assignment doesn't work.. it must be window.onscroll.
			// So we need to invent a really funny way to make it work.
			var myScrollHandler = function() {
					scrollFunc();
					arguments.callee.prevScrollHandler.apply( this, arguments );
				};
			win.$.setTimeout( function() {
				myScrollHandler.prevScrollHandler = window.onscroll ||
				function() {};
				window.onscroll = myScrollHandler;
			}, 0 );
			scrollFunc();
		}
	}

	function hideCover( editor ) {
		if ( !currentCover )
			return;

		editor.focusManager.remove( currentCover );
		var win = CKEDITOR.document.getWindow();
		currentCover.hide();
		win.removeListener( 'resize', resizeCover );

		if ( CKEDITOR.env.ie6Compat ) {
			win.$.setTimeout( function() {
				var prevScrollHandler = window.onscroll && window.onscroll.prevScrollHandler;
				window.onscroll = prevScrollHandler || null;
			}, 0 );
		}
		resizeCover = null;
	}

	function removeCovers() {
		for ( var coverId in covers )
			covers[ coverId ].remove();
		covers = {};
	}

	var accessKeyProcessors = {};

	var accessKeyDownHandler = function( evt ) {
			var ctrl = evt.data.$.ctrlKey || evt.data.$.metaKey,
				alt = evt.data.$.altKey,
				shift = evt.data.$.shiftKey,
				key = String.fromCharCode( evt.data.$.keyCode ),
				keyProcessor = accessKeyProcessors[ ( ctrl ? 'CTRL+' : '' ) + ( alt ? 'ALT+' : '' ) + ( shift ? 'SHIFT+' : '' ) + key ];

			if ( !keyProcessor || !keyProcessor.length )
				return;

			keyProcessor = keyProcessor[ keyProcessor.length - 1 ];
			keyProcessor.keydown && keyProcessor.keydown.call( keyProcessor.uiElement, keyProcessor.dialog, keyProcessor.key );
			evt.data.preventDefault();
		};

	var accessKeyUpHandler = function( evt ) {
			var ctrl = evt.data.$.ctrlKey || evt.data.$.metaKey,
				alt = evt.data.$.altKey,
				shift = evt.data.$.shiftKey,
				key = String.fromCharCode( evt.data.$.keyCode ),
				keyProcessor = accessKeyProcessors[ ( ctrl ? 'CTRL+' : '' ) + ( alt ? 'ALT+' : '' ) + ( shift ? 'SHIFT+' : '' ) + key ];

			if ( !keyProcessor || !keyProcessor.length )
				return;

			keyProcessor = keyProcessor[ keyProcessor.length - 1 ];
			if ( keyProcessor.keyup ) {
				keyProcessor.keyup.call( keyProcessor.uiElement, keyProcessor.dialog, keyProcessor.key );
				evt.data.preventDefault();
			}
		};

	var registerAccessKey = function( uiElement, dialog, key, downFunc, upFunc ) {
			var procList = accessKeyProcessors[ key ] || ( accessKeyProcessors[ key ] = [] );
			procList.push( {
				uiElement: uiElement,
				dialog: dialog,
				key: key,
				keyup: upFunc || uiElement.accessKeyUp,
				keydown: downFunc || uiElement.accessKeyDown
			} );
		};

	var unregisterAccessKey = function( obj ) {
			for ( var i in accessKeyProcessors ) {
				var list = accessKeyProcessors[ i ];
				for ( var j = list.length - 1; j >= 0; j-- ) {
					if ( list[ j ].dialog == obj || list[ j ].uiElement == obj )
						list.splice( j, 1 );
				}
				if ( list.length === 0 )
					delete accessKeyProcessors[ i ];
			}
		};

	var tabAccessKeyUp = function( dialog, key ) {
			if ( dialog._.accessKeyMap[ key ] )
				dialog.selectPage( dialog._.accessKeyMap[ key ] );
		};

	var tabAccessKeyDown = function() {};

	( function() {
		CKEDITOR.ui.dialog = {
			/**
			 * The base class of all dialog UI elements.
			 *
			 * @class CKEDITOR.ui.dialog.uiElement
			 * @constructor Creates a uiElement class instance.
			 * @param {CKEDITOR.dialog} dialog Parent dialog object.
			 * @param {CKEDITOR.dialog.definition.uiElement} elementDefinition Element
			 * definition.
			 *
			 * Accepted fields:
			 *
			 * * `id` (Required) The id of the UI element. See {@link CKEDITOR.dialog#getContentElement}.
			 * * `type` (Required) The type of the UI element. The
			 *     value to this field specifies which UI element class will be used to
			 *     generate the final widget.
			 * * `title` (Optional) The popup tooltip for the UI
			 *     element.
			 * * `hidden` (Optional) A flag that tells if the element
			 *     should be initially visible.
			 * * `className` (Optional) Additional CSS class names
			 *     to add to the UI element. Separated by space.
			 * * `style` (Optional) Additional CSS inline styles
			 *     to add to the UI element. A semicolon (;) is required after the last
			 *     style declaration.
			 * * `accessKey` (Optional) The alphanumeric access key
			 *     for this element. Access keys are automatically prefixed by CTRL.
			 * * `on*` (Optional) Any UI element definition field that
			 *     starts with `on` followed immediately by a capital letter and
			 *     probably more letters is an event handler. Event handlers may be further
			 *     divided into registered event handlers and DOM event handlers. Please
			 *     refer to {@link CKEDITOR.ui.dialog.uiElement#registerEvents} and
			 *     {@link CKEDITOR.ui.dialog.uiElement#eventProcessors} for more information.
			 *
			 * @param {Array} htmlList
			 * List of HTML code to be added to the dialog's content area.
			 * @param {Function/String} [nodeNameArg='div']
			 * A function returning a string, or a simple string for the node name for
			 * the root DOM node.
			 * @param {Function/Object} [stylesArg={}]
			 * A function returning an object, or a simple object for CSS styles applied
			 * to the DOM node.
			 * @param {Function/Object} [attributesArg={}]
			 * A fucntion returning an object, or a simple object for attributes applied
			 * to the DOM node.
			 * @param {Function/String} [contentsArg='']
			 * A function returning a string, or a simple string for the HTML code inside
			 * the root DOM node. Default is empty string.
			 */
			uiElement: function( dialog, elementDefinition, htmlList, nodeNameArg, stylesArg, attributesArg, contentsArg ) {
				if ( arguments.length < 4 )
					return;

				var nodeName = ( nodeNameArg.call ? nodeNameArg( elementDefinition ) : nodeNameArg ) || 'div',
					html = [ '<', nodeName, ' ' ],
					styles = ( stylesArg && stylesArg.call ? stylesArg( elementDefinition ) : stylesArg ) || {},
					attributes = ( attributesArg && attributesArg.call ? attributesArg( elementDefinition ) : attributesArg ) || {},
					innerHTML = ( contentsArg && contentsArg.call ? contentsArg.call( this, dialog, elementDefinition ) : contentsArg ) || '',
					domId = this.domId = attributes.id || CKEDITOR.tools.getNextId() + '_uiElement',
					i;

				if ( elementDefinition.requiredContent && !dialog.getParentEditor().filter.check( elementDefinition.requiredContent ) ) {
					styles.display = 'none';
					this.notAllowed = true;
				}

				// Set the id, a unique id is required for getElement() to work.
				attributes.id = domId;

				// Set the type and definition CSS class names.
				var classes = {};
				if ( elementDefinition.type )
					classes[ 'cke_dialog_ui_' + elementDefinition.type ] = 1;
				if ( elementDefinition.className )
					classes[ elementDefinition.className ] = 1;
				if ( elementDefinition.disabled )
					classes.cke_disabled = 1;

				var attributeClasses = ( attributes[ 'class' ] && attributes[ 'class' ].split ) ? attributes[ 'class' ].split( ' ' ) : [];
				for ( i = 0; i < attributeClasses.length; i++ ) {
					if ( attributeClasses[ i ] )
						classes[ attributeClasses[ i ] ] = 1;
				}
				var finalClasses = [];
				for ( i in classes )
					finalClasses.push( i );
				attributes[ 'class' ] = finalClasses.join( ' ' );

				// Set the popup tooltop.
				if ( elementDefinition.title )
					attributes.title = elementDefinition.title;

				// Write the inline CSS styles.
				var styleStr = ( elementDefinition.style || '' ).split( ';' );

				// Element alignment support.
				if ( elementDefinition.align ) {
					var align = elementDefinition.align;
					styles[ 'margin-left' ] = align == 'left' ? 0 : 'auto';
					styles[ 'margin-right' ] = align == 'right' ? 0 : 'auto';
				}

				for ( i in styles )
					styleStr.push( i + ':' + styles[ i ] );
				if ( elementDefinition.hidden )
					styleStr.push( 'display:none' );
				for ( i = styleStr.length - 1; i >= 0; i-- ) {
					if ( styleStr[ i ] === '' )
						styleStr.splice( i, 1 );
				}
				if ( styleStr.length > 0 )
					attributes.style = ( attributes.style ? ( attributes.style + '; ' ) : '' ) + styleStr.join( '; ' );

				// Write the attributes.
				for ( i in attributes )
					html.push( i + '="' + CKEDITOR.tools.htmlEncode( attributes[ i ] ) + '" ' );

				// Write the content HTML.
				html.push( '>', innerHTML, '</', nodeName, '>' );

				// Add contents to the parent HTML array.
				htmlList.push( html.join( '' ) );

				( this._ || ( this._ = {} ) ).dialog = dialog;

				// Override isChanged if it is defined in element definition.
				if ( typeof elementDefinition.isChanged == 'boolean' )
					this.isChanged = function() {
						return elementDefinition.isChanged;
					};
				if ( typeof elementDefinition.isChanged == 'function' )
					this.isChanged = elementDefinition.isChanged;

				// Overload 'get(set)Value' on definition.
				if ( typeof elementDefinition.setValue == 'function' ) {
					this.setValue = CKEDITOR.tools.override( this.setValue, function( org ) {
						return function( val ) {
							org.call( this, elementDefinition.setValue.call( this, val ) );
						};
					} );
				}

				if ( typeof elementDefinition.getValue == 'function' ) {
					this.getValue = CKEDITOR.tools.override( this.getValue, function( org ) {
						return function() {
							return elementDefinition.getValue.call( this, org.call( this ) );
						};
					} );
				}

				// Add events.
				CKEDITOR.event.implementOn( this );

				this.registerEvents( elementDefinition );
				if ( this.accessKeyUp && this.accessKeyDown && elementDefinition.accessKey )
					registerAccessKey( this, dialog, 'CTRL+' + elementDefinition.accessKey );

				var me = this;
				dialog.on( 'load', function() {
					var input = me.getInputElement();
					if ( input ) {
						var focusClass = me.type in { 'checkbox': 1, 'ratio': 1 } && CKEDITOR.env.ie && CKEDITOR.env.version < 8 ? 'cke_dialog_ui_focused' : '';
						input.on( 'focus', function() {
							dialog._.tabBarMode = false;
							dialog._.hasFocus = true;
							me.fire( 'focus' );
							focusClass && this.addClass( focusClass );

						} );

						input.on( 'blur', function() {
							me.fire( 'blur' );
							focusClass && this.removeClass( focusClass );
						} );
					}
				} );

				// Completes this object with everything we have in the
				// definition.
				CKEDITOR.tools.extend( this, elementDefinition );

				// Register the object as a tab focus if it can be included.
				if ( this.keyboardFocusable ) {
					this.tabIndex = elementDefinition.tabIndex || 0;

					this.focusIndex = dialog._.focusList.push( this ) - 1;
					this.on( 'focus', function() {
						dialog._.currentFocusIndex = me.focusIndex;
					} );
				}
			},

			/**
			 * Horizontal layout box for dialog UI elements, auto-expends to available width of container.
			 *
			 * @class CKEDITOR.ui.dialog.hbox
			 * @extends CKEDITOR.ui.dialog.uiElement
			 * @constructor Creates a hbox class instance.
			 * @param {CKEDITOR.dialog} dialog Parent dialog object.
			 * @param {Array} childObjList
			 * Array of {@link CKEDITOR.ui.dialog.uiElement} objects inside this container.
			 * @param {Array} childHtmlList
			 * Array of HTML code that correspond to the HTML output of all the
			 * objects in childObjList.
			 * @param {Array} htmlList
			 * Array of HTML code that this element will output to.
			 * @param {CKEDITOR.dialog.definition.uiElement} elementDefinition
			 * The element definition. Accepted fields:
			 *
			 * * `widths` (Optional) The widths of child cells.
			 * * `height` (Optional) The height of the layout.
			 * * `padding` (Optional) The padding width inside child cells.
			 * * `align` (Optional) The alignment of the whole layout.
			 */
			hbox: function( dialog, childObjList, childHtmlList, htmlList, elementDefinition ) {
				if ( arguments.length < 4 )
					return;

				this._ || ( this._ = {} );

				var children = this._.children = childObjList,
					widths = elementDefinition && elementDefinition.widths || null,
					height = elementDefinition && elementDefinition.height || null,
					styles = {},
					i;
				/** @ignore */
				var innerHTML = function() {
						var html = [ '<tbody><tr class="cke_dialog_ui_hbox">' ];
						for ( i = 0; i < childHtmlList.length; i++ ) {
							var className = 'cke_dialog_ui_hbox_child',
								styles = [];
							if ( i === 0 ) {
								className = 'cke_dialog_ui_hbox_first';
							}
							if ( i == childHtmlList.length - 1 ) {
								className = 'cke_dialog_ui_hbox_last';
							}

							html.push( '<td class="', className, '" role="presentation" ' );
							if ( widths ) {
								if ( widths[ i ] ) {
									styles.push( 'width:' + cssLength( widths[i] ) );
								}
							} else {
								styles.push( 'width:' + Math.floor( 100 / childHtmlList.length ) + '%' );
							}
							if ( height ) {
								styles.push( 'height:' + cssLength( height ) );
							}
							if ( elementDefinition && elementDefinition.padding !== undefined ) {
								styles.push( 'padding:' + cssLength( elementDefinition.padding ) );
							}
							// In IE Quirks alignment has to be done on table cells. (https://dev.ckeditor.com/ticket/7324)
							if ( CKEDITOR.env.ie && CKEDITOR.env.quirks && children[ i ].align ) {
								styles.push( 'text-align:' + children[ i ].align );
							}
							if ( styles.length > 0 ) {
								html.push( 'style="' + styles.join( '; ' ) + '" ' );
							}
							html.push( '>', childHtmlList[ i ], '</td>' );
						}
						html.push( '</tr></tbody>' );
						return html.join( '' );
					};

				var attribs = { role: 'presentation' };
				elementDefinition && elementDefinition.align && ( attribs.align = elementDefinition.align );

				CKEDITOR.ui.dialog.uiElement.call( this, dialog, elementDefinition || { type: 'hbox' }, htmlList, 'table', styles, attribs, innerHTML );
			},

			/**
			 * Vertical layout box for dialog UI elements.
			 *
			 * @class CKEDITOR.ui.dialog.vbox
			 * @extends CKEDITOR.ui.dialog.hbox
			 * @constructor Creates a vbox class instance.
			 * @param {CKEDITOR.dialog} dialog Parent dialog object.
			 * @param {Array} childObjList
			 * Array of {@link CKEDITOR.ui.dialog.uiElement} objects inside this container.
			 * @param {Array} childHtmlList
			 * Array of HTML code that correspond to the HTML output of all the
			 * objects in childObjList.
			 * @param {Array} htmlList Array of HTML code that this element will output to.
			 * @param {CKEDITOR.dialog.definition.uiElement} elementDefinition
			 * The element definition. Accepted fields:
			 *
			 * * `width` (Optional) The width of the layout.
			 * * `heights` (Optional) The heights of individual cells.
			 * * `align` (Optional) The alignment of the layout.
			 * * `padding` (Optional) The padding width inside child cells.
			 * * `expand` (Optional) Whether the layout should expand
			 *     vertically to fill its container.
			 */
			vbox: function( dialog, childObjList, childHtmlList, htmlList, elementDefinition ) {
				if ( arguments.length < 3 )
					return;

				this._ || ( this._ = {} );

				var children = this._.children = childObjList,
					width = elementDefinition && elementDefinition.width || null,
					heights = elementDefinition && elementDefinition.heights || null;
				/** @ignore */
				var innerHTML = function() {
						var html = [ '<table role="presentation" cellspacing="0" border="0" ' ];
						html.push( 'style="' );
						if ( elementDefinition && elementDefinition.expand )
							html.push( 'height:100%;' );
						html.push( 'width:' + cssLength( width || '100%' ), ';' );

						// (https://dev.ckeditor.com/ticket/10123) Temp fix for dialog broken layout in latest webkit.
						if ( CKEDITOR.env.webkit )
							html.push( 'float:none;' );

						html.push( '"' );
						html.push( 'align="', CKEDITOR.tools.htmlEncode(
						( elementDefinition && elementDefinition.align ) || ( dialog.getParentEditor().lang.dir == 'ltr' ? 'left' : 'right' ) ), '" ' );

						html.push( '><tbody>' );
						for ( var i = 0; i < childHtmlList.length; i++ ) {
							var styles = [];
							html.push( '<tr><td role="presentation" ' );
							if ( width )
								styles.push( 'width:' + cssLength( width || '100%' ) );
							if ( heights )
								styles.push( 'height:' + cssLength( heights[ i ] ) );
							else if ( elementDefinition && elementDefinition.expand )
								styles.push( 'height:' + Math.floor( 100 / childHtmlList.length ) + '%' );
							if ( elementDefinition && elementDefinition.padding !== undefined )
								styles.push( 'padding:' + cssLength( elementDefinition.padding ) );
							// In IE Quirks alignment has to be done on table cells. (https://dev.ckeditor.com/ticket/7324)
							if ( CKEDITOR.env.ie && CKEDITOR.env.quirks && children[ i ].align )
								styles.push( 'text-align:' + children[ i ].align );
							if ( styles.length > 0 )
								html.push( 'style="', styles.join( '; ' ), '" ' );
							html.push( ' class="cke_dialog_ui_vbox_child">', childHtmlList[ i ], '</td></tr>' );
						}
						html.push( '</tbody></table>' );
						return html.join( '' );
					};
				CKEDITOR.ui.dialog.uiElement.call( this, dialog, elementDefinition || { type: 'vbox' }, htmlList, 'div', null, { role: 'presentation' }, innerHTML );
			}
		};
	} )();

	/** @class CKEDITOR.ui.dialog.uiElement */
	CKEDITOR.ui.dialog.uiElement.prototype = {
		/**
		 * Gets the root DOM element of this dialog UI object.
		 *
		 *		uiElement.getElement().hide();
		 *
		 * @returns {CKEDITOR.dom.element} Root DOM element of UI object.
		 */
		getElement: function() {
			return CKEDITOR.document.getById( this.domId );
		},

		/**
		 * Gets the DOM element that the user inputs values.
		 *
		 * This function is used by {@link #setValue}, {@link #getValue} and {@link #focus}. It should
		 * be overrided in child classes where the input element isn't the root
		 * element.
		 *
		 *		var rawValue = textInput.getInputElement().$.value;
		 *
		 * @returns {CKEDITOR.dom.element} The element where the user input values.
		 */
		getInputElement: function() {
			return this.getElement();
		},

		/**
		 * Gets the parent dialog object containing this UI element.
		 *
		 *		var dialog = uiElement.getDialog();
		 *
		 * @returns {CKEDITOR.dialog} Parent dialog object.
		 */
		getDialog: function() {
			return this._.dialog;
		},

		/**
		 * Sets the value of this dialog UI object.
		 *
		 *		uiElement.setValue( 'Dingo' );
		 *
		 * @chainable
		 * @param {Object} value The new value.
		 * @param {Boolean} noChangeEvent Internal commit, to supress `change` event on this element.
		 */
		setValue: function( value, noChangeEvent ) {
			this.getInputElement().setValue( value );
			!noChangeEvent && this.fire( 'change', { value: value } );
			return this;
		},

		/**
		 * Gets the current value of this dialog UI object.
		 *
		 *		var myValue = uiElement.getValue();
		 *
		 * @returns {Object} The current value.
		 */
		getValue: function() {
			return this.getInputElement().getValue();
		},

		/**
		 * Tells whether the UI object's value has changed.
		 *
		 *		if ( uiElement.isChanged() )
		 *			confirm( 'Value changed! Continue?' );
		 *
		 * @returns {Boolean} `true` if changed, `false` if not changed.
		 */
		isChanged: function() {
			// Override in input classes.
			return false;
		},

		/**
		 * Selects the parent tab of this element. Usually called by focus() or overridden focus() methods.
		 *
		 *		focus : function() {
		 *			this.selectParentTab();
		 *			// do something else.
		 *		}
		 *
		 * @chainable
		 */
		selectParentTab: function() {
			var element = this.getInputElement(),
				cursor = element,
				tabId;
			while ( ( cursor = cursor.getParent() ) && cursor.$.className.search( 'cke_dialog_page_contents' ) == -1 ) {

			}

			// Some widgets don't have parent tabs (e.g. OK and Cancel buttons).
			if ( !cursor )
				return this;

			tabId = cursor.getAttribute( 'name' );
			// Avoid duplicate select.
			if ( this._.dialog._.currentTabId != tabId )
				this._.dialog.selectPage( tabId );
			return this;
		},

		/**
		 * Puts the focus to the UI object. Switches tabs if the UI object isn't in the active tab page.
		 *
		 *		uiElement.focus();
		 *
		 * @chainable
		 */
		focus: function() {
			this.selectParentTab().getInputElement().focus();
			return this;
		},

		/**
		 * Registers the `on*` event handlers defined in the element definition.
		 *
		 * The default behavior of this function is:
		 *
		 * 1. If the on* event is defined in the class's eventProcesors list,
		 *     then the registration is delegated to the corresponding function
		 *     in the eventProcessors list.
		 * 2. If the on* event is not defined in the eventProcessors list, then
		 *     register the event handler under the corresponding DOM event of
		 *     the UI element's input DOM element (as defined by the return value
		 *     of {@link #getInputElement}).
		 *
		 * This function is only called at UI element instantiation, but can
		 * be overridded in child classes if they require more flexibility.
		 *
		 * @chainable
		 * @param {CKEDITOR.dialog.definition.uiElement} definition The UI element
		 * definition.
		 */
		registerEvents: function( definition ) {
			var regex = /^on([A-Z]\w+)/,
				match;

			var registerDomEvent = function( uiElement, dialog, eventName, func ) {
					dialog.on( 'load', function() {
						uiElement.getInputElement().on( eventName, func, uiElement );
					} );
				};

			for ( var i in definition ) {
				if ( !( match = i.match( regex ) ) )
					continue;
				if ( this.eventProcessors[ i ] )
					this.eventProcessors[ i ].call( this, this._.dialog, definition[ i ] );
				else
					registerDomEvent( this, this._.dialog, match[ 1 ].toLowerCase(), definition[ i ] );
			}

			return this;
		},

		/**
		 * The event processor list used by
		 * {@link CKEDITOR.ui.dialog.uiElement#getInputElement} at UI element
		 * instantiation. The default list defines three `on*` events:
		 *
		 * 1. `onLoad` - Called when the element's parent dialog opens for the
		 *     first time.
		 * 2. `onShow` - Called whenever the element's parent dialog opens.
		 * 3. `onHide` - Called whenever the element's parent dialog closes.
		 *
		 *		// This connects the 'click' event in CKEDITOR.ui.dialog.button to onClick
		 *		// handlers in the UI element's definitions.
		 *		CKEDITOR.ui.dialog.button.eventProcessors = CKEDITOR.tools.extend( {},
		 *			CKEDITOR.ui.dialog.uiElement.prototype.eventProcessors,
		 *			{ onClick : function( dialog, func ) { this.on( 'click', func ); } },
		 *			true
		 *		);
		 *
		 * @property {Object}
		 */
		eventProcessors: {
			onLoad: function( dialog, func ) {
				dialog.on( 'load', func, this );
			},

			onShow: function( dialog, func ) {
				dialog.on( 'show', func, this );
			},

			onHide: function( dialog, func ) {
				dialog.on( 'hide', func, this );
			}
		},

		/**
		 * The default handler for a UI element's access key down event, which
		 * tries to put focus to the UI element.
		 *
		 * Can be overridded in child classes for more sophisticaed behavior.
		 *
		 * @param {CKEDITOR.dialog} dialog The parent dialog object.
		 * @param {String} key The key combination pressed. Since access keys
		 * are defined to always include the `CTRL` key, its value should always
		 * include a `'CTRL+'` prefix.
		 */
		accessKeyDown: function() {
			this.focus();
		},

		/**
		 * The default handler for a UI element's access key up event, which
		 * does nothing.
		 *
		 * Can be overridded in child classes for more sophisticated behavior.
		 *
		 * @param {CKEDITOR.dialog} dialog The parent dialog object.
		 * @param {String} key The key combination pressed. Since access keys
		 * are defined to always include the `CTRL` key, its value should always
		 * include a `'CTRL+'` prefix.
		 */
		accessKeyUp: function() {},

		/**
		 * Disables a UI element.
		 */
		disable: function() {
			var element = this.getElement(),
				input = this.getInputElement();
			input.setAttribute( 'disabled', 'true' );
			element.addClass( 'cke_disabled' );
		},

		/**
		 * Enables a UI element.
		 */
		enable: function() {
			var element = this.getElement(),
				input = this.getInputElement();
			input.removeAttribute( 'disabled' );
			element.removeClass( 'cke_disabled' );
		},

		/**
		 * Determines whether an UI element is enabled or not.
		 *
		 * @returns {Boolean} Whether the UI element is enabled.
		 */
		isEnabled: function() {
			return !this.getElement().hasClass( 'cke_disabled' );
		},

		/**
		 * Determines whether an UI element is visible or not.
		 *
		 * @returns {Boolean} Whether the UI element is visible.
		 */
		isVisible: function() {
			return this.getInputElement().isVisible();
		},

		/**
		 * Determines whether an UI element is focus-able or not.
		 * Focus-able is defined as being both visible and enabled.
		 *
		 * @returns {Boolean} Whether the UI element can be focused.
		 */
		isFocusable: function() {
			if ( !this.isEnabled() || !this.isVisible() )
				return false;
			return true;
		}
	};

	/** @class CKEDITOR.ui.dialog.hbox */
	CKEDITOR.ui.dialog.hbox.prototype = CKEDITOR.tools.extend( new CKEDITOR.ui.dialog.uiElement(), {
		/**
		 * Gets a child UI element inside this container.
		 *
		 *		var checkbox = hbox.getChild( [0,1] );
		 *		checkbox.setValue( true );
		 *
		 * @param {Array/Number} indices An array or a single number to indicate the child's
		 * position in the container's descendant tree. Omit to get all the children in an array.
		 * @returns {Array/CKEDITOR.ui.dialog.uiElement} Array of all UI elements in the container
		 * if no argument given, or the specified UI element if indices is given.
		 */
		getChild: function( indices ) {
			// If no arguments, return a clone of the children array.
			if ( arguments.length < 1 )
				return this._.children.concat();

			// If indices isn't array, make it one.
			if ( !indices.splice )
				indices = [ indices ];

			// Retrieve the child element according to tree position.
			if ( indices.length < 2 )
				return this._.children[ indices[ 0 ] ];
			else
				return ( this._.children[ indices[ 0 ] ] && this._.children[ indices[ 0 ] ].getChild ) ? this._.children[ indices[ 0 ] ].getChild( indices.slice( 1, indices.length ) ) : null;
		}
	}, true );

	CKEDITOR.ui.dialog.vbox.prototype = new CKEDITOR.ui.dialog.hbox();

	( function() {
		var commonBuilder = {
			build: function( dialog, elementDefinition, output ) {
				var children = elementDefinition.children,
					child,
					childHtmlList = [],
					childObjList = [];
				for ( var i = 0;
				( i < children.length && ( child = children[ i ] ) ); i++ ) {
					var childHtml = [];
					childHtmlList.push( childHtml );
					childObjList.push( CKEDITOR.dialog._.uiElementBuilders[ child.type ].build( dialog, child, childHtml ) );
				}
				return new CKEDITOR.ui.dialog[ elementDefinition.type ]( dialog, childObjList, childHtmlList, output, elementDefinition );
			}
		};

		CKEDITOR.dialog.addUIElement( 'hbox', commonBuilder );
		CKEDITOR.dialog.addUIElement( 'vbox', commonBuilder );
	} )();

	/**
	 * Generic dialog command. It opens a specific dialog when executed.
	 *
	 *		// Register the "link" command which opens the "link" dialog.
	 *		editor.addCommand( 'link', new CKEDITOR.dialogCommand( 'link' ) );
	 *
	 * @class
	 * @constructor Creates a dialogCommand class instance.
	 * @extends CKEDITOR.commandDefinition
	 * @param {String} dialogName The name of the dialog to open when executing
	 * this command.
	 * @param {Object} [ext] Additional command definition's properties.
	 * @param {String} [ext.tabId] You can provide additional property (`tabId`) if you wish to open the dialog on a specific tabId.
	 *
	 *		// Open the dialog on the 'keystroke' tabId.
	 *		editor.addCommand( 'keystroke', new CKEDITOR.dialogCommand( 'a11yHelp', { tabId: 'keystroke' } ) );
	 */
	CKEDITOR.dialogCommand = function( dialogName, ext ) {
		this.dialogName = dialogName;
		CKEDITOR.tools.extend( this, ext, true );
	};

	CKEDITOR.dialogCommand.prototype = {
		exec: function( editor ) {
			var tabId = this.tabId;
			editor.openDialog( this.dialogName, function( dialog ) {
				// Select different tab if it's provided (#830).
				if ( tabId ) {
					dialog.selectPage( tabId );
				}
			} );
		},

		// Dialog commands just open a dialog ui, thus require no undo logic,
		// undo support should dedicate to specific dialog implementation.
		canUndo: false,

		editorFocus: 1
	};

	( function() {
		var notEmptyRegex = /^([a]|[^a])+$/,
			integerRegex = /^\d*$/,
			numberRegex = /^\d*(?:\.\d+)?$/,
			htmlLengthRegex = /^(((\d*(\.\d+))|(\d*))(px|\%)?)?$/,
			cssLengthRegex = /^(((\d*(\.\d+))|(\d*))(px|em|ex|in|cm|mm|pt|pc|\%)?)?$/i,
			inlineStyleRegex = /^(\s*[\w-]+\s*:\s*[^:;]+(?:;|$))*$/;

		CKEDITOR.VALIDATE_OR = 1;
		CKEDITOR.VALIDATE_AND = 2;

		CKEDITOR.dialog.validate = {
			functions: function() {
				var args = arguments;
				return function() {
					/**
					 * It's important for validate functions to be able to accept the value
					 * as argument in addition to this.getValue(), so that it is possible to
					 * combine validate functions together to make more sophisticated
					 * validators.
					 */
					var value = this && this.getValue ? this.getValue() : args[ 0 ];

					var msg,
						relation = CKEDITOR.VALIDATE_AND,
						functions = [],
						i;

					for ( i = 0; i < args.length; i++ ) {
						if ( typeof args[ i ] == 'function' )
							functions.push( args[ i ] );
						else
							break;
					}

					if ( i < args.length && typeof args[ i ] == 'string' ) {
						msg = args[ i ];
						i++;
					}

					if ( i < args.length && typeof args[ i ] == 'number' )
						relation = args[ i ];

					var passed = ( relation == CKEDITOR.VALIDATE_AND ? true : false );
					for ( i = 0; i < functions.length; i++ ) {
						if ( relation == CKEDITOR.VALIDATE_AND )
							passed = passed && functions[ i ]( value );
						else
							passed = passed || functions[ i ]( value );
					}

					return !passed ? msg : true;
				};
			},

			regex: function( regex, msg ) {
				/*
				 * Can be greatly shortened by deriving from functions validator if code size
				 * turns out to be more important than performance.
				 */
				return function() {
					var value = this && this.getValue ? this.getValue() : arguments[ 0 ];
					return !regex.test( value ) ? msg : true;
				};
			},

			notEmpty: function( msg ) {
				return this.regex( notEmptyRegex, msg );
			},

			integer: function( msg ) {
				return this.regex( integerRegex, msg );
			},

			'number': function( msg ) {
				return this.regex( numberRegex, msg );
			},

			'cssLength': function( msg ) {
				return this.functions( function( val ) {
					return cssLengthRegex.test( CKEDITOR.tools.trim( val ) );
				}, msg );
			},

			'htmlLength': function( msg ) {
				return this.functions( function( val ) {
					return htmlLengthRegex.test( CKEDITOR.tools.trim( val ) );
				}, msg );
			},

			'inlineStyle': function( msg ) {
				return this.functions( function( val ) {
					return inlineStyleRegex.test( CKEDITOR.tools.trim( val ) );
				}, msg );
			},

			equals: function( value, msg ) {
				return this.functions( function( val ) {
					return val == value;
				}, msg );
			},

			notEqual: function( value, msg ) {
				return this.functions( function( val ) {
					return val != value;
				}, msg );
			}
		};

		CKEDITOR.on( 'instanceDestroyed', function( evt ) {
			// Remove dialog cover on last instance destroy.
			if ( CKEDITOR.tools.isEmpty( CKEDITOR.instances ) ) {
				var currentTopDialog;
				while ( ( currentTopDialog = CKEDITOR.dialog._.currentTop ) )
					currentTopDialog.hide();
				removeCovers();
			}

			var dialogs = evt.editor._.storedDialogs;
			for ( var name in dialogs )
				dialogs[ name ].destroy();

		} );

	} )();

	// Extend the CKEDITOR.editor class with dialog specific functions.
	CKEDITOR.tools.extend( CKEDITOR.editor.prototype, {
		/**
		 * Loads and opens a registered dialog.
		 *
		 *		CKEDITOR.instances.editor1.openDialog( 'smiley' );
		 *
		 * @member CKEDITOR.editor
		 * @param {String} dialogName The registered name of the dialog.
		 * @param {Function} callback The function to be invoked after dialog instance created.
		 * @returns {CKEDITOR.dialog} The dialog object corresponding to the dialog displayed.
		 * `null` if the dialog name is not registered.
		 * @see CKEDITOR.dialog#add
		 */
		openDialog: function( dialogName, callback ) {
			var dialog = null, dialogDefinitions = CKEDITOR.dialog._.dialogDefinitions[ dialogName ];

			if ( CKEDITOR.dialog._.currentTop === null )
				showCover( this );

			// If the dialogDefinition is already loaded, open it immediately.
			if ( typeof dialogDefinitions == 'function' ) {
				var storedDialogs = this._.storedDialogs || ( this._.storedDialogs = {} );

				dialog = storedDialogs[ dialogName ] || ( storedDialogs[ dialogName ] = new CKEDITOR.dialog( this, dialogName ) );

				callback && callback.call( dialog, dialog );
				dialog.show();

			} else if ( dialogDefinitions == 'failed' ) {
				hideCover( this );
				throw new Error( '[CKEDITOR.dialog.openDialog] Dialog "' + dialogName + '" failed when loading definition.' );
			} else if ( typeof dialogDefinitions == 'string' ) {

				CKEDITOR.scriptLoader.load( CKEDITOR.getUrl( dialogDefinitions ),
					function() {
						var dialogDefinition = CKEDITOR.dialog._.dialogDefinitions[ dialogName ];
						// In case of plugin error, mark it as loading failed.
						if ( typeof dialogDefinition != 'function' )
							CKEDITOR.dialog._.dialogDefinitions[ dialogName ] = 'failed';

						this.openDialog( dialogName, callback );
					}, this, 0, 1 );
			}

			CKEDITOR.skin.loadPart( 'dialog' );

			return dialog;
		}
	} );
} )();

CKEDITOR.plugins.add( 'dialog', {
	requires: 'dialogui',
	init: function( editor ) {
		editor.on( 'doubleclick', function( evt ) {
			if ( evt.data.dialog )
				editor.openDialog( evt.data.dialog );
		}, null, null, 999 );
	}
} );

// Dialog related configurations.

/**
 * The color of the dialog background cover. It should be a valid CSS color string.
 *
 *		config.dialog_backgroundCoverColor = 'rgb(255, 254, 253)';
 *
 * @cfg {String} [dialog_backgroundCoverColor='white']
 * @member CKEDITOR.config
 */

/**
 * The opacity of the dialog background cover. It should be a number within the
 * range `[0.0, 1.0]`.
 *
 *		config.dialog_backgroundCoverOpacity = 0.7;
 *
 * @cfg {Number} [dialog_backgroundCoverOpacity=0.5]
 * @member CKEDITOR.config
 */

/**
 * If the dialog has more than one tab, put focus into the first tab as soon as dialog is opened.
 *
 *		config.dialog_startupFocusTab = true;
 *
 * @cfg {Boolean} [dialog_startupFocusTab=false]
 * @member CKEDITOR.config
 */

/**
 * The distance of magnetic borders used in moving and resizing dialogs,
 * measured in pixels.
 *
 *		config.dialog_magnetDistance = 30;
 *
 * @cfg {Number} [dialog_magnetDistance=20]
 * @member CKEDITOR.config
 */

/**
 * The guideline to follow when generating the dialog buttons. There are 3 possible options:
 *
 * * `'OS'` - the buttons will be displayed in the default order of the user's OS;
 * * `'ltr'` - for Left-To-Right order;
 * * `'rtl'` - for Right-To-Left order.
 *
 * Example:
 *
 *		config.dialog_buttonsOrder = 'rtl';
 *
 * @since 3.5
 * @cfg {String} [dialog_buttonsOrder='OS']
 * @member CKEDITOR.config
 */

/**
 * The dialog contents to removed. It's a string composed by dialog name and tab name with a colon between them.
 *
 * Separate each pair with semicolon (see example).
 *
 * **Note:** All names are case-sensitive.
 *
 * **Note:** Be cautious when specifying dialog tabs that are mandatory,
 * like `'info'`, dialog functionality might be broken because of this!
 *
 *		config.removeDialogTabs = 'flash:advanced;image:Link';
 *
 * @since 3.5
 * @cfg {String} [removeDialogTabs='']
 * @member CKEDITOR.config
 */

/**
 * Tells if user should not be asked to confirm close, if any dialog field was modified.
 * By default it is set to `false` meaning that the confirmation dialog will be shown.
 *
 *		config.dialog_noConfirmCancel = true;
 *
 * @since 4.3
 * @cfg {Boolean} [dialog_noConfirmCancel=false]
 * @member CKEDITOR.config
 */

/**
 * Event fired when a dialog definition is about to be used to create a dialog into
 * an editor instance. This event makes it possible to customize the definition
 * before creating it.
 *
 * Note that this event is called only the first time a specific dialog is
 * opened. Successive openings will use the cached dialog, and this event will
 * not get fired.
 *
 * @event dialogDefinition
 * @member CKEDITOR
 * @param {CKEDITOR.dialog.definition} data The dialog defination that
 * is being loaded.
 * @param {CKEDITOR.editor} editor The editor instance that will use the dialog.
 */

/**
 * Event fired when a tab is going to be selected in a dialog.
 *
 * @event selectPage
 * @member CKEDITOR.dialog
 * @param data
 * @param {String} data.page The id of the page that it's gonna be selected.
 * @param {String} data.currentPage The id of the current page.
 */

/**
 * Event fired when the user tries to dismiss a dialog.
 *
 * @event cancel
 * @member CKEDITOR.dialog
 * @param data
 * @param {Boolean} data.hide Whether the event should proceed or not.
 */

/**
 * Event fired when the user tries to confirm a dialog.
 *
 * @event ok
 * @member CKEDITOR.dialog
 * @param data
 * @param {Boolean} data.hide Whether the event should proceed or not.
 */

/**
 * Event fired when a dialog is shown.
 *
 * @event show
 * @member CKEDITOR.dialog
 */

/**
 * Event fired when a dialog is shown.
 *
 * @event dialogShow
 * @member CKEDITOR.editor
 * @param {CKEDITOR.editor} editor This editor instance.
 * @param {CKEDITOR.dialog} data The opened dialog instance.
 */

/**
 * Event fired when a dialog is hidden.
 *
 * @event hide
 * @member CKEDITOR.dialog
 */

/**
 * Event fired when a dialog is hidden.
 *
 * @event dialogHide
 * @member CKEDITOR.editor
 * @param {CKEDITOR.editor} editor This editor instance.
 * @param {CKEDITOR.dialog} data The hidden dialog instance.
 */

/**
 * Event fired when a dialog is being resized. The event is fired on
 * both the {@link CKEDITOR.dialog} object and the dialog instance
 * since 3.5.3, previously it was only available in the global object.
 *
 * @static
 * @event resize
 * @member CKEDITOR.dialog
 * @param data
 * @param {CKEDITOR.dialog} data.dialog The dialog being resized (if
 * it is fired on the dialog itself, this parameter is not sent).
 * @param {String} data.skin The skin name.
 * @param {Number} data.width The new width.
 * @param {Number} data.height The new height.
 */

/**
 * Event fired when a dialog is being resized. The event is fired on
 * both the {@link CKEDITOR.dialog} object and the dialog instance
 * since 3.5.3, previously it was only available in the global object.
 *
 * @since 3.5
 * @event resize
 * @member CKEDITOR.dialog
 * @param data
 * @param {Number} data.width The new width.
 * @param {Number} data.height The new height.
 */

/**
 * Event fired when the dialog state changes, usually by {@link CKEDITOR.dialog#setState}.
 *
 * @since 4.5
 * @event state
 * @member CKEDITOR.dialog
 * @param data
 * @param {Number} data The new state. Either {@link CKEDITOR#DIALOG_STATE_IDLE} or {@link CKEDITOR#DIALOG_STATE_BUSY}.
 */
