Bug 143430 [CommonNavigator] CommonNavigator requires initialInput to be Adaptable
I have a root nodes that is not Adaptable and that does not fit well with CommonNavigator.getInitialInput which requires (for no real good reason ?) to be Adaptable. Should this not just be an Object ?
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonNavigator.java
* Constructs and returns an instance of {@link CommonViewer}. The ID of
	 * the Eclipse view part will be used to create the viewer. The ID is
	 * important as some extensions indicate they should only be used with a
	 * particular viewer ID.
	 * <p>
	 * 
	 * @param aParent
	 *            A composite parent to contain the Common Viewer
	 * @return An initialized instance of CommonViewer
	 */
	protected CommonViewer createCommonViewer(Composite aParent) {
		CommonViewer aViewer = new CommonViewer(getViewSite().getId(), aParent,
				SWT.MULTI | SWT.H_SCROLL | SWT.V_SCROLL);
		initListeners(aViewer);
		aViewer.getNavigatorContentService().restoreState(memento);
		return aViewer;
	}
	/**
	 * <p>
	 * Adds the listeners to the Common Viewer.
	 * </p>
	 * 
	 * @param viewer
	 *            The viewer
	 * @since 2.0
	 */
	protected void initListeners(TreeViewer viewer) {
		viewer.addDoubleClickListener(new IDoubleClickListener() {
			public void doubleClick(DoubleClickEvent event) {
				try {