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
Set descriptors = findDescriptorsWithPossibleChild(anElement, false);
		for (Iterator iter = descriptors.iterator(); iter.hasNext();) {
			INavigatorContentDescriptor descriptor = (INavigatorContentDescriptor) iter
					.next();
			if (descriptor.hasOverridingExtensions()) {
				overrideableExtensions.add(getExtension(descriptor));
			}
		}
		return overrideableExtensions;
	}
	/*
	 * (Non-Javadoc)
	 * 
	 * @see INavigatorContentService#getContentDescriptorById(String)
	 */
	public INavigatorContentDescriptor getContentDescriptorById(
			String anExtensionId) {
		return CONTENT_DESCRIPTOR_REGISTRY.getContentDescriptor(anExtensionId);
	}
	/**
	 * 
	 * @param anExtensionId
	 *            The id used to define the
	 *            <b>org.eclipse.ui.navigator.navigatorContent
	 *            /navigatorContent</b> extension.
	 * @return An instance of the content extension for the given extension id.
	 *         May return <b>null</b> if the id is invalid.
	 */
	public INavigatorContentExtension getContentExtensionById(
			String anExtensionId) {