Does anyone happen to have tried implementing a feature where you could drag and drop something outside the application, and a new window would be created as a result of the drop?

There is a feature like that for example in opera browser as I recall. You can drag and drop a tab outside opera's window and then a new window is created.

I have been playing around with this for a while but I can't figure out any working solution.
I am connected to QDrag::targetChanged(QWidget*) signal and the target seems always to be null when moving a drag outside my window.
Btw, I have tried to install an event filter on QApplication::desktop() but it seems to get never called..

Any tip would be highly appreciated!