Bug 217801 [CommonNavigator] Capability filtering of commonWizard extensions uses wrong identifier
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/internal/navigator/wizards/CommonWizardDescriptor.java
* value of the associatedExtensionId
		 *  
		 * Code elsewhere anticipates that this attribute may be null, so there is 
		 * no need to set it to a default non-null value. Indeed, this will cause
		 * incorrect behavior. 
		 * */
		if(id == null) {
			id = configElement.getAttribute(ATT_ASSOCIATED_EXTENSION_ID);
		}
		if (wizardId == null || wizardId.length() == 0) {
			throw new WorkbenchException("Missing attribute: " + 
					ATT_WIZARD_ID + " in common wizard extension: " + 
					configElement.getDeclaringExtension().getNamespaceIdentifier());
		}
		if (type == null || type.length() == 0) {
			throw new WorkbenchException("Missing attribute: " + 
					ATT_TYPE + " in common wizard extension: " + 
					configElement.getDeclaringExtension().getNamespaceIdentifier());
		}
		IConfigurationElement[] children = configElement
				.getChildren(TAG_ENABLEMENT);
		if (children.length == 1) {
			try {
				enablement = ElementHandler.getDefault().create(
						ExpressionConverter.getDefault(), children[0]);
			} catch (CoreException e) {
				NavigatorPlugin.log(IStatus.ERROR, 0, e.getMessage(), e);
			}
		} else if (children.length > 1) {
			throw new WorkbenchException("More than one element: " +