Bug 26221 [Perspectives] Noticeable menubar "flash" when switching perspectives
Build 20021113 Note this is Windows XP. Open a Java Perspective. Open a Java Browsing Perspective. Switch back and forth between the two. On my XP machine I can visibly see the menu bar "shrink" as menu items are removed, then "expand" as menu items are added. It actually looks like it's animated. Anyway, very noticeable and somewhat strange since I'm switching between two perspectives that have the same base menus (i.e., the menu bar for each perspective is the same).
bundles/org.eclipse.jface/src/org/eclipse/jface/action/MenuManager.java
/**
	 * The menu control; <code>null</code> before
	 * creation and after disposal.
	 */
	private Menu menu = null;
	
	/**
	 * List of registered menu listeners (element type: <code>IMenuListener</code>).
	 */
	private ListenerList listeners = new ListenerList(1);
	/**
	 * The menu id.
	 */
	private String id;
	/**
	 * The menu item widget; <code>null</code> before
	 * creation and after disposal. This field is used
	 * when this menu manager is a sub-menu.
	 */
	private MenuItem menuItem;
	/**
	 * The text for a sub-menu.
	 */
	private String menuText;