Bug 64855 QuickMenuAction leaks the context menus
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/actions/QuickMenuAction.java
* Hook to compute the menu location if the focus widget is
	 * a styled text widget.
	 * 
	 * @param text the styled text widget that has the focus
	 * 
	 * @return a widget relative position of the menu to pop up or
	 *  <code>null</code> if now position inside the widget can
	 *  be computed
	 */
	protected Point computeMenuLocation(StyledText text) {
		Point result= text.getLocationAtOffset(text.getCaretOffset());
		result.y+= text.getLineHeight();
		if (!text.getClientArea().contains(result))
			return null;
		return result;
	}
	
	/**
	 * Hook to compute the menu location if the focus widget is
	 * a tree widget.
	 * 
	 * @param tree the tree widget that has the focus
	 * 
	 * @return a widget relative position of the menu to pop up or
	 *  <code>null</code> if now position inside the widget can
	 *  be computed
	 */
	protected Point computeMenuLocation(Tree tree) {
		TreeItem[] items= tree.getSelection();
		Rectangle clientArea= tree.getClientArea();