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
protected boolean isRootExtension(String anExtensionId) {
		return assistant.isRootExtension(anExtensionId);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.eclipse.ui.internal.navigator.INavigatorContentService#removeListener
	 * (
	 * org.eclipse.ui.internal.navigator.extensions.INavigatorContentServiceListener
	 * )
	 */
	public void removeListener(INavigatorContentServiceListener aListener) {
		listeners.remove(aListener);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see java.lang.Object#toString()
	 */
	public String toString() {
		return "ContentService[" + viewerDescriptor.getViewerId() + "]"; 
	}
	private void notifyListeners(NavigatorContentExtension aDescriptorInstance) {
		if (listeners.size() == 0) {
			return;
		}
		INavigatorContentServiceListener listener = null;
		List failedListeners = null;
		for (Iterator listenersItr = listeners.iterator(); listenersItr