Hello, The problem you describe looks like the next upstream issue : https://github.com/mypaint/mypaint/issues/1292
And a fix for the 2.x branch is there : https://github.com/mypaint/mypaint/commit/8ebfaf6de916e9734d79a86dd598ed1c57dcc77d Hoping it applies without complain. Best regard Rémi
