public void DetachStopsListeningForChanges() { var region = new MockPresentationRegion(); var behavior = new RegionActiveAwareBehavior { Region = region }; var collection = region.MockActiveViews.Items; behavior.Attach(); behavior.Detach(); ActiveAwareFrameworkElement activeAwareObject = new ActiveAwareFrameworkElement(); collection.Add(activeAwareObject); Assert.IsFalse(activeAwareObject.IsActive); }