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
if (childMem != null) {
			ArrayList elements= new ArrayList();
			IMemento[] elementMem= childMem.getChildren(TAG_ELEMENT);
			for (int i= 0; i < elementMem.length; i++) {
				Object element= JavaCore.create(elementMem[i].getString(TAG_PATH));
				elements.add(element);
			}
			fViewer.setExpandedElements(elements.toArray());
		}
	}
	
	/**
	 * Create the KeyListener for doing the refresh on the viewer.
	 */
	private void initRefreshKey() {
		fViewer.getControl().addKeyListener(new KeyAdapter() {
			public void keyReleased(KeyEvent event) {
				if (event.keyCode == SWT.F5) {
					fRefreshAction.selectionChanged(
						(IStructuredSelection) fViewer.getSelection());
					if (fRefreshAction.isEnabled())
						fRefreshAction.run();
				}
			}
		});
	}
	
	void initFrameList() {
		fFrameSource= new PackagesFrameSource(this);
		fFrameList= new FrameList(fFrameSource);