Task Notification, task edit form

Hi,

I noticed ( at least for my current installation) that notification is not triggered when the tasks are edited by node edit form (it is triggered by the 'Update task and add new comment' form). The same things happen when comments are edited. I wonder if this is a default feature or a bug? If this is a feature, is there anyway to turn on the notification when tasks are edited by node edit form.

Thanks,

peijun zhang