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
* <p>
 * {@link org.eclipse.ui.navigator.NavigatorActionService}: Manages instances
 * of {@link org.eclipse.ui.navigator.CommonActionProvider}s provided by
 * individual extensions and content extensions.
 * </p>
 * </li>
 * <li>
 * <p>
 * {@link org.eclipse.ui.navigator.INavigatorContentService}: Manages instances
 * of Navigator Content Extensions. Instances are created as needed, and
 * disposed of upon the disposal of the Navigator Content Service.
 * </p>
 * </li>
 * </ul>
 * <p>
 * Clients are not expected to subclass CommonNavigator. Clients that wish to
 * define their own custom extensible navigator view need to specify an instance
 * of the <b>org.eclipse.ui.views</b> extension point:
 * 
 * <pre>
 *   
 *          &lt;extension
 *          		point=&quot;org.eclipse.ui.views&quot;&gt;
 *          	&lt;view
 *          		name=&quot;My Custom View&quot;
 *          		icon=&quot;relative/path/to/icon.gif&quot;
 *          		category=&quot;org.acme.mycategory&quot;
 *          		class=&quot;org.eclipse.ui.navigator.CommonNavigator&quot;
 *          		id=&quot;org.acme.MyCustomNavigatorID&quot;&gt;
 *          	&lt;/view&gt;