Bug 63420 [R21PRES] Flash on tab switch
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21EditorStackPresentation.java
boolean getShellActivated() {
		Window window = getWindow();
		if (window instanceof WorkbenchWindow)
			return ((WorkbenchWindow) window).getShellActivated();
		return false;
	}
	/**
	 * Returns the top level window.
	 * 
	 * @return Window the window for the receiver
	 */
	public Window getWindow() {
		Control ctrl = getControl();
		if (ctrl != null) {
			Object data = ctrl.getShell().getData();
			if (data instanceof Window)
				return (Window) data;
		}
		return null;
	}
	/**
	 * Creates the tab item for the specified part.
	 * 
	 * @param part
	 * @param tabIndex
	 * @return the tab item for the part
	 */
	private CTabItem createPartTab(IPresentablePart part, int tabIndex) {
		CTabItem tabItem = new CTabItem(tabFolder, SWT.NONE, tabIndex);
		tabItem.setData(TAB_DATA, part);