How to clear task and start new activity from widget

I have an application with the following activities

MainActivity > DetailActivity

If I start the DetailActivity from the MainActivity using the following flags in my intent

intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK|Intent.FLAG_ACTIVITY_NEW_TASK);

The current task will be cleared and a new task will be started with only DetailActivity on the stack.

However, if I currently have MainActivity on the stack, and I start a new instance of MainActivity from the a widget using the same flags, I get two instances of MainActivity overlaying each-other.

Is it not possible to clear the task and start a new instance of MainActivity from the widget?