Or you can switch between QPainter<->OpenGL canvas to and fro to get it activated
Git commit ab8c23437eb49c0fbdb5793b30a92b0b7fa8c4f1 by Dmitry Kazakov. Committed on 21/01/2013 at 09:31. Pushed by dkazakov into branch 'master'. Fixed resetting the canvas on changing trilinear filter oprion M +9 -1 krita/ui/canvas/kis_canvas2.cpp http://commits.kde.org/calligra/ab8c23437eb49c0fbdb5793b30a92b0b7fa8c4f1