Bug 302791 [CommonNavigator] Associated editor does not close when deleting resource (editorInput) through CommonNavigator
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/wizards/CommonWizardDescriptor.java
* Determine if this content extension is enabled for the given element.
	 * 
	 * @param anElement
	 *            The element that should be used for the evaluation.
	 * @return True if and only if the extension is enabled for the element.
	 */
	public boolean isEnabledFor(Object anElement) {
		if (enablement == null) {
			return false;
		}
		try {
			IEvaluationContext context = NavigatorPlugin.getEvalContext(anElement);
			return (enablement.evaluate(context) == EvaluationResult.TRUE);
		} catch (CoreException e) {
			NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
		}
		return false;
	}
	void init() throws WorkbenchException { 
		wizardId = configElement.getAttribute(ATT_WIZARD_ID);
		type = configElement.getAttribute(ATT_TYPE);
		
		menuGroupId = configElement.getAttribute(ATT_MENU_GROUP_ID);
		if(menuGroupId == null) {
			menuGroupId = DEFAULT_MENU_GROUP_ID;
		}
		
		/* 
		 * The id defaults to the id of the enclosing navigatorContent extension, if any
		 * If not enclosed, this can be null initially, so it will default to the