Bug 194209 [CommonNavigator] ProblemsLabelDecorator does not scale well with Project Explorer
When opening a project, The ProblemsLabelDecorator fires a LabelProviderChangedEvent for all resources contained in this project. While in a ProblemTreeViewer, like the Package Explorer, this is handled in an optimized way by filtering out updates to resources which are not realized in the tree view, the Common Navigator has no such means. The result is that for a project with e.g. 50000 resources, a label update for 50000 elements is triggered even though the project is not even expanded in the view.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonNavigator.java
* <p>
	 * Provides access to the commonViewer used by the current CommonNavigator.
	 * The field will not be valid until after
	 * {@link #init(IViewSite, IMemento)}&nbsp;has been called by the
	 * Workbench.
	 * </p>
	 *  
	 * @return The (already created) instance of Common Viewer.
	 */
	public CommonViewer getCommonViewer() {
		return commonViewer;
	}
	/**
	 * @return The Navigator Content Service which populates this instance of
	 *         Common Navigator
	 */
	public INavigatorContentService getNavigatorContentService() {
		return getCommonViewer().getNavigatorContentService();
	}
	/**
	 * Returns an object which is an instance of the given class
	 * associated with this object. Returns <code>null</code> if
	 * no such object can be found.
	 *
	 * @param adapter the adapter class to look up
	 * @return a object castable to the given class, 
	 *    or <code>null</code> if this object does not
	 *    have an adapter for the given class
	 */
	public Object getAdapter(Class adapter) {