Bug 12585 Packages view should not provide file and resource transfer if Java element below CU is selected
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
IActionBars actionBars= getViewSite().getActionBars();
			fActionSet.fillToolBar(actionBars.getToolBarManager());
			actionBars.updateActionBars();
			
			boolean showCUChildren= JavaBasePreferencePage.showCompilationUnitChildren();
			((JavaElementContentProvider)fViewer.getContentProvider()).setProvideMembers(showCUChildren);
			
			refreshViewer= true;
		}			
		if (refreshViewer)
			fViewer.refresh();
	}
	private IPropertyChangeListener addWorkingSetChangeSupport() {
		final IPropertyChangeListener propertyChangeListener= createWorkingSetChangeListener();
		final IWorkbenchPage page= getSite().getPage();
		fWorkingSetFilter= new ResourceWorkingSetFilter();
		fViewer.addFilter(fWorkingSetFilter);
		
		if (page.getWorkingSet() != null)		
			page.getWorkingSet().addPropertyChangeListener(propertyChangeListener);				
		
		
		page.addPropertyChangeListener(propertyChangeListener);
		
		
		fViewer.getControl().addDisposeListener(new DisposeListener() {
			public void widgetDisposed(DisposeEvent e) {
				if (page!= null)
					page.removePropertyChangeListener(propertyChangeListener);
			}