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
}
		return super.getAdapter(key);
	}
	/**
	 * Returns the tool tip text for the given element.
	 */
	String getToolTipText(Object element) {
		String result;
		if (!(element instanceof IResource)) {
			if (element instanceof IJavaModel) {
				result= PackagesMessages.getString("PackageExplorerPart.workspace"); 
			} else if (element instanceof IJavaElement){
				result= JavaElementLabels.getTextLabel(element, AppearanceAwareLabelProvider.DEFAULT_TEXTFLAGS);
			} else if (element instanceof IWorkingSet) {
				result= ((IWorkingSet)element).getName();
			} else if (element instanceof WorkingSetModel) {
				result= PackagesMessages.getString("PackageExplorerPart.workingSetModel"); 
			} else {
				result= fLabelProvider.getText(element);
			}
		} else {
			IPath path= ((IResource) element).getFullPath();
			if (path.isRoot()) {
				result= PackagesMessages.getString("PackageExplorer.title"); 
			} else {
				result= path.makeRelative().toString();
			}
		}
		
		if (fWorkingSetName == null)