While the liquify transform is enabled if we zoom in the image we get black checkerboard pattern all over. If zoom out we see the image again. Also using tablet applies the transformation without even clicking. Reproducible: Always you can see a screen-cast of the problem here : https://dl.dropboxusercontent.com/u/37777793/Kazam_screencast_00000.mp4
Yes, I can confirm this on my nvidia/proprietary driver/ubuntu desktop. With a 5000x5000 image, no selection, selecting liquify makes the screen go black.
Git commit 0e4827191f1713bd9e603f9999e5601138308ed5 by Boudewijn Rempt. Committed on 29/01/2015 at 10:33. Pushed by rempt into branch 'calligra/2.9'. M +3 -0 krita/ui/tool/kis_tool_freehand.cc http://commits.kde.org/calligra/0e4827191f1713bd9e603f9999e5601138308ed5
I cannot reproduce this anymore. (Though liquify on a 5000x5000 image is _really_ slow...