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/internal/navigator/extensions/LinkHelperService.java
*/
	public LinkHelperService(NavigatorContentService aContentService) {
		contentService = aContentService;
	}
	/**
	 * 
	 * @param anObject
	 *            An object from the viewer
	 * @return An array of link helpers that know about elements in the
	 *         selection or null
	 */
	public ILinkHelper[] getLinkHelpersFor(Object anObject) {
		LinkHelperDescriptor[] descriptors = LinkHelperManager.getInstance()
				.getLinkHelpersFor(anObject, contentService);
		if (descriptors.length == 0) {
			return CANT_GET_NO_HELP;
		}
		Set helpers = new LinkedHashSet();
		for (int i = 0; i < descriptors.length; i++) {
			helpers.add(getLinkHelper(descriptors[i]));
		}
		if (helpers.size() == 0)
			return CANT_GET_NO_HELP;
		return (ILinkHelper[]) helpers.toArray(new ILinkHelper[helpers.size()]);
	}
	/**
	 * 
	 * @param input
	 *            The Editor input from the active viewer.
	 * @return An array of link helpers that know about elements in the