Bug 4373 Packages View - double clich doesn't expand two hiearchy levels
- enable: Show CU children in packages view - double click on CU observe: only one level gets expanded - now expand a node by clicking on the + observe: two levels get expanded
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
private Shell getShell() {
		return fViewer.getTree().getShell();
	}
	/**
	 * Returns the selection provider.
	 */
	private ISelectionProvider getSelectionProvider() {
		return fViewer;
	}
	
	/**
	 * 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.
	 */
	public void menuAboutToShow(IMenuManager menu) {
		JavaPlugin.createStandardGroups(menu);
		IStructuredSelection selection= (IStructuredSelection) fViewer.getSelection();
		boolean selectionHasElements= !selection.isEmpty();
		Object element= selection.getFirstElement();
		
		if (selection.size() == 1 && fViewer.isExpandable(element))