How to recover phantom widgets?

I have a grouping plasmoid that i accidentally dragged into the dock, but when i dragged it out it vanished! And I dont see a way to recover it. How would I delete the phantom widgets (and their data) or atleast drag them back onto the desktop?

apparently connecting an external monitor allows you to reposition the widget so that it reappears, will come back to this thread if it disappears again.