fault value for the URL field.
			var urlField = infoTab.get( 'url' );
			urlField['default'] = 'www.example.com';

			// Remove the "Target" tab from the "Link" dialog.
			dialogDefinition.removeContents( 'target' );

			// Add a new tab to the "Link" dialog.
			dialogDefinition.addContents({
				id : 'customTab',
				label : 'My Tab',
				accessKey : 'M',
				elements : [
					{
						id : 'myField1',
						type : 'text',
						label : 'My Text Field'
					},
					{
						id : 'myField2',
						type : 'te