Bug 189490 [CommonNavigator] Go To->Resource won't enable
I0524 1. Open the Project Explorer in the Resource perspective 2. Create a vanilla project P 3. Create a folder F 4. Create a file resource R Open the Navigate->Go To file. "Resource..." will remain disabled.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
public boolean isActive(String anExtensionId) {
		return assistant.isActive(anExtensionId);
	}
	public boolean isVisible(String anExtensionId) {
		return assistant.isVisible(anExtensionId);
	}
	protected final Collection getExtensions() {
		return (contentExtensions.size() > 0) ? Collections
				.unmodifiableCollection(contentExtensions.values())
				: Collections.EMPTY_LIST;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.ui.internal.navigator.INavigatorContentService#addListener
	 * (org
	 * .eclipse.ui.internal.navigator.extensions.INavigatorContentServiceListener
	 * )
	 */
	public void addListener(INavigatorContentServiceListener aListener) {
		listeners.add(aListener);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.ui.navigator.INavigatorContentService#getFilterService()
	 */
	public INavigatorFilterService getFilterService() {
		if (navigatorFilterService == null) {