function isConfigured( definition, tabId, elementId )
	{
		if ( elementId.indexOf( ";" ) !== -1 )
		{
			var ids = elementId.split( ";" );
			for ( var i = 0 ; i < ids.length ; i++ )
			{
				if ( isConfigured( definition, tabId, ids[i]) )
					return true;
			}
			return false;
		}

		var elementFileBrowser = definition.getContents( tabId ).get( elementId ).filebrowser;
		return ( elementFileBrowser && elementFileBrowser.url );
	}
Returns true if filebrowser is configured in one of the elements.

@param {CKEDITOR.dialog.dialogDefinitionObject}
           definition Dialog definition.
@param String
           tabId The tab id where element(s) can be found.
@param String
           elementId The element id (or ids, separated with a semicolon) to check.