Bug 81426 Package Explorer shows nothing after drill into working set, then show projects
I200412160800 - switch Package Explorer to working sets - context menu > Go Into a working set - Show > Projects -> view is empty -> view toolbar button 'Up to Working Sets' does not do anything
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
String message= PackagesMessages.getString("PackageExplorer.removeFilters"); 
            if (MessageDialog.openQuestion(getSite().getShell(), PackagesMessages.getString("PackageExplorer.filteredDialog.title"), message)) { 
                filterGroup.setFilters(filters);		
                if (revealElementOrParent(element))
                    return true;
            }
        }
        FrameAction action= fActionSet.getUpAction();
        while (action.getFrameList().getCurrentIndex() > 0) {
        	
        	 
        	if (action.getFrameList().getSource().getFrame(IFrameSource.PARENT_FRAME, 0) == null)
        		break; 
            action.run();
            if (revealElementOrParent(element))
                return true;
        }
        return false;
    }
    
    private boolean revealElementOrParent(Object element) {
        if (revealAndVerify(element))
		    return true;
		element= getVisibleParent(element);
		if (element != null) {
		    if (revealAndVerify(element))
		        return true;
		    if (element instanceof IJavaElement) {
		        IResource resource= ((IJavaElement)element).getResource();
		        if (resource != null) {