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
boolean showCUChildren= JavaBasePreferencePage.showCompilationUnitChildren();
		fViewer.setContentProvider(new JavaElementContentProvider(showCUChildren, false));
		
		JavaPlugin.getDefault().getProblemMarkerManager().addListener(fViewer);		
		JavaPlugin.getDefault().getPreferenceStore().addPropertyChangeListener(this);
		
		fJavaElementLabelProvider= 
			new StandardJavaUILabelProvider(
				StandardJavaUILabelProvider.DEFAULT_TEXTFLAGS | JavaElementLabels.P_COMPRESSED,
				StandardJavaUILabelProvider.DEFAULT_IMAGEFLAGS | JavaElementImageProvider.SMALL_ICONS,
				StandardJavaUILabelProvider.getAdornmentProviders(true, null)
			);
		
		fViewer.setLabelProvider(new DecoratingLabelProvider(
			fJavaElementLabelProvider, PlatformUI.getWorkbench().getDecoratorManager())
		);
		fViewer.setSorter(new JavaElementSorter());
		fViewer.addFilter(new EmptyInnerPackageFilter());
		fViewer.setUseHashlookup(true);
		fViewer.addFilter(fPatternFilter);
		fViewer.addFilter(fLibraryFilter);
		
		addWorkingSetChangeSupport();
		IWorkingSet workingSet= getSite().getPage().getWorkingSet();
		if (workingSet != null) {
			fWorkingSetFilter= new ResourceWorkingSetFilter();
			fWorkingSetFilter.setWorkingSet(workingSet);		
			fViewer.addFilter(fWorkingSetFilter);
		}