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
if (result.length() == 0)
			return wsstr;
		return Messages.format(PackagesMessages.PackageExplorer_toolTip2, new String[] { result, fWorkingSetLabel }); 
	}
	
	public String getTitleToolTip() {
		if (fViewer == null)
			return super.getTitleToolTip();
		return getToolTipText(fViewer.getInput());
	}
	
	/**
	 * @see IWorkbenchPart#setFocus()
	 */
	public void setFocus() {
		fViewer.getTree().setFocus();
	}
	/**
	 * Returns the current selection.
	 */
	private ISelection getSelection() {
		return fViewer.getSelection();
	}
	  
	
	
	/**
	 * Called when the context menu is about to open. Override
	 * to add your own context dependent menu contributions.
	 */