Bug 189636 Custom rule template failing
Null poonter exception being thrown when trying to add a custom rule which is causing the rule cretion to fail. Also there is a minor typo in the rule template string.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/NavigatorContentService.java
}
			}
		}
		if (rootExtensions.isEmpty()) {
			return findContentExtensionsByTriggerPoint(anElement);
		}
		return rootExtensions;
	}
	/**
	 * Search for extensions that declare the given element in their
	 * <b>possibleChildren</b> expression.
	 * 
	 * @param anElement
	 *            The element to use in the query
	 * @return The set of {@link INavigatorContentExtension}s that are
	 *         <i>visible</i> and <i>active</i> for this content service and
	 *         have a <b>possibleChildren</b> expression that is <i>enabled</i>
	 *         for the given element.
	 */
	public Set findOverrideableContentExtensionsByTriggerPoint(
			Object anElement) {
		Set overrideableExtensions = new TreeSet(
				ExtensionPriorityComparator.INSTANCE);
		Set descriptors = findDescriptorsByTriggerPoint(anElement);
		for (Iterator iter = descriptors.iterator(); iter.hasNext();) {
			INavigatorContentDescriptor descriptor = (INavigatorContentDescriptor) iter
					.next();
			if (descriptor.hasOverridingExtensions()) {
				overrideableExtensions.add(getExtension(descriptor));
			}