free floating popup menu

What do you think about this?: I have a virtual folder f.e 'my documents'. i go to 'my music', then to 'rock'. because i am going to use the folder 'rock' often for the next time. i can put it out, so that i have a freefloating menu of the folder 'rock' that only closes when i click something (f.e a close button at the top of the menu)

It's been mentioned before, and it's been marked as a 'good idea'