Cue, Copy, Paste, Crash

Got the Black Screen with cursor today.

RoadHog4 v1.2.1 b550
QTver 4.7.0

Had CueList, Groups, Programmer windows open.
Opened a List, right clicked a cue, copy
Closed List, Opened another, right clicked a cue in this list,
As soon as I clicked paste the screen went black.

The only thing that wasnt running was desktop
Killed desktop, restarted it. All is well now.

Anyone else have this problem before.