Bug 127105 Package explorer hierarchical mode calls ICompilationUnit#getChildren() in PackageExplorerProblemTreeViewer#isExpandable
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
}
	/**
	 * 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.PackageExplorerPart_workspace; 
			} else if (element instanceof IJavaElement){
				result= JavaElementLabels.getTextLabel(element, AppearanceAwareLabelProvider.DEFAULT_TEXTFLAGS);
			} else if (element instanceof IWorkingSet) {
				result= ((IWorkingSet)element).getLabel();
			} else if (element instanceof WorkingSetModel) {
				result= PackagesMessages.PackageExplorerPart_workingSetModel; 
			} else {
				result= fLabelProvider.getText(element);
			}
		} else {
			IPath path= ((IResource) element).getFullPath();
			if (path.isRoot()) {
				result= PackagesMessages.PackageExplorer_title; 
			} else {
				result= path.makeRelative().toString();
			}
		}
		
		if (fWorkingSetLabel == null)
			return result;
		String wsstr= Messages.format(PackagesMessages.PackageExplorer_toolTip, new String[] { fWorkingSetLabel });