Bug 81372 Package Explorer working set mode can't be restored anymore
M4 test pass - create project - go into this project - press go up to show all projects again - switch to working set mode - close Eclipe - restart observe: Package explorer comes up in project mode again. Even if you switch to working set mode again the package explorer will be in project mode on every restart. Problem is that the package explorer restores the last frame on restart which in this case is alwasy the JavaModel.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
if (!isFlatLayout() && object instanceof IPackageFragment) {
					IPackageFragment fragment = (IPackageFragment) object;
					return !fragment.isDefaultPackage() && fragment.hasSubpackages();
				}
			} catch (JavaModelException e) {
				JavaPlugin.log(e);
			}
			return false;
		}
		
		protected void handleInvalidSelection(ISelection invalidSelection, ISelection newSelection) {
			IStructuredSelection is= (IStructuredSelection)invalidSelection;
			List ns= null;
			if (newSelection instanceof IStructuredSelection) {
				ns= new ArrayList(((IStructuredSelection)newSelection).toList());
			} else {
				ns= new ArrayList();
			}
			boolean changed= false;
			for (Iterator iter= is.iterator(); iter.hasNext();) {
				Object element= iter.next();
				if (element instanceof IJavaProject) {
					IProject project= ((IJavaProject)element).getProject();
					if (!project.isOpen()) {
						ns.add(project);
						changed= true;
					}
				} else if (element instanceof IProject) {
					IProject project= (IProject)element;
					if (project.isOpen()) {