Bug 169591 [Common Navigator] Show In fails for editor inputs
The show(ShowInContext) method for CommonNavigator only considers the selection of the context. When Show In Project Explorer is performed from an editor, the selection is empty and the input is provided. Unfortunately, this is problematic, as the show-in target needs to adapt the input to an IFile so this will probably need to have some sort of extension so that the Project Explorer can plug-in the proper support.
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 {