Hog v4.1.0 'Remove Fixtures' seems to have a bug

v4.1.0

I had approx 260 RGBW cells in my show file (imported from v3). I selected a range of them in the fixture window and pressed 'Remove Fixtures'. I got the normal warning dialogue box, and confirmed. The fixtures were not removed and then when I selected any of them and pressed 'Remove Fixtures', nothing happened. I re-booted but further attempts to delete them produce the same result.