code: 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 (#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 );
  		}
docs: 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.