Window title bars disappears when using Gwenview

[luggw1]

I seem to be having a problem where the title bar (the bar at the top with the control box, window title, minimize, maximize and close buttons) on all windows disappear when I open Gwenview enough times (I haven't counted the exact number). The only solution seems to be restarting the computer - I tried just logging out, but the desktop hangs.

Is anyone else experiencing this? Is there a solution to this problem? It's quite annoying and in the most recent case interrupted a software update that was in progress.

Thanks for the help.
Bill Lugg