Cocoa - keep the drop down menu w/o closing it until a task is done

I added a status menu onto the menu bar (upper right corner).

Now one of the menu item, once clicked, will invoke some sort of executions behind the scene. while waiting for the execution to be done, I added a readonly menu item to update the state of the execution. So I want to show the execution state in a readonly menu item, which means the menu need to be kept dropping down until the execution is done.

I开发者_如何转开发s there any way to do that?