Bug 27764 IResource.findMarkers is called too often
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
fViewer.setUseHashlookup(true);
		
		MenuManager menuMgr= new MenuManager("#PopupMenu"); 
		menuMgr.setRemoveAllWhenShown(true);
		menuMgr.addMenuListener(this);
		fContextMenu= menuMgr.createContextMenu(fViewer.getTree());
		fViewer.getTree().setMenu(fContextMenu);
		
		
		IWorkbenchPartSite site= getSite();
		site.registerContextMenu(menuMgr, fViewer);
		site.setSelectionProvider(fViewer);
		site.getPage().addPartListener(fPartListener);
		
		makeActions(); 
		
		
		
		fViewer.setInput(findInputElement());
		initDragAndDrop();
		initKeyListener();
			
		fSelectionListener= new ISelectionChangedListener() {
			public void selectionChanged(SelectionChangedEvent event) {
				handleSelectionChanged(event);
			}
		};
		fViewer.addSelectionChangedListener(fSelectionListener);
		
		fViewer.addDoubleClickListener(new IDoubleClickListener() {