Bug 63420 [R21PRES] Flash on tab switch
bundles/org.eclipse.ui.presentations.r21/src/org/eclipse/ui/internal/presentations/R21BasicStackPresentation.java
*/
	public StackDropResult dragOver(Control currentControl, Point location) {
		
		Point localPos = paneFolder.getControl().toControl(location);
		final CTabItem tabUnderPointer = paneFolder.getItem(localPos);
		
		
		if (tabUnderPointer == null)
			return null;
		
		int dragOverIndex = paneFolder.indexOf(tabUnderPointer);
		return new StackDropResult(Geometry.toDisplay(paneFolder.getControl(),
				tabUnderPointer.getBounds()), new Integer(dragOverIndex));
	}
	/**
	 * Returns the toolbar control for the currently selected part, or null if
	 * none (not all parts have a toolbar).
	 * 
	 * @return the current toolbar or null if none
	 */
	protected Control getCurrentToolbar() {
		IPresentablePart part = getCurrentPart();
		if (part == null) {
			return null;
		}
		return part.getToolBar();
	}
	/*
	 * (non-Javadoc)
	 *