Bug 220559 Regression in some open editor performance tests
Verifying build I20080226-1155, it looks like some open editors tests are seriously red: - OpenJavaEditorTest#testOpenEditor3(): between -16.1% and -36% - OpenJavaEditorTest#testOpenEditor4(): between -18.1% and -39.2%
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonNavigator.java
TreeViewer viewer = getCommonViewer();
			if (viewer.isExpandable(element)) {
				viewer.setExpandedState(element, !viewer.getExpandedState(element));
			}
		}
	}
	/**
	 * <p>
	 * The Common Navigator Manager handles the setup of the Common Navigator
	 * Menu, manages updates to the ActionBars from
	 * {@link CommonActionProvider}&nbsp; extensions as the user's selection
	 * changes, and also updates the status bar based on the current selection.
	 * 
	 * @return The Common Navigator Manager class which handles menu population
	 *         and ActionBars
	 */
	protected CommonNavigatorManager createCommonManager() {
		return new CommonNavigatorManager(this, memento);
	}
	/**
	 * <p>
	 * The ActionGroup is used to populate the ActionBars of Common Navigator
	 * View Part, and the returned implementation will have an opportunity to
	 * fill the ActionBars of the view as soon as it is created. ({@link ActionGroup#fillActionBars(org.eclipse.ui.IActionBars)}.
	 * </p>
	 * <p>
	 * The default implementation returns an action group which will add the
	 * following actions:
	 * <ul>