Bug 63420 [R21PRES] Flash on tab switch
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21EditorStackPresentation.java
private CTabFolder tabFolder;
	
	private Listener dragListener = new Listener() {
		public void handleEvent(Event event) {
			Point localPos = new Point(event.x, event.y);
			CTabItem tabUnderPointer = tabFolder.getItem(localPos);
			if (tabUnderPointer == null) {
				
				if (getSite().isStackMoveable())
					getSite().dragStart(tabFolder.toDisplay(localPos), false);
				return;
			}
			IPresentablePart part = getPartForTab(tabUnderPointer);
			if (getSite().isPartMoveable(part)) {
				
				getSite().dragStart(part, tabFolder.toDisplay(localPos), false);
			}
		}
	};
	
	private CTabFolderListener closeListener = new CTabFolderListener() {
		public void itemClosed(CTabFolderEvent e) {
			CTabItem item = (CTabItem) e.item;
			if (null != item) {
				e.doit = false; 
				getSite().close(new IPresentablePart[] { getPartForTab(item) });
			}
		}
	};