I recorded a video of the issues: http://virvel.de/kritabug.mp4 Everything works fine so long as painting only happens in one of the views. Painting into the second view results in all kinds of glitchyness. Switching back to the first view and making a stroke fixes all the glitchyness/performance degradations. Sometimes when trying to paint in the secondary view, the brush outline goes crazy and takes on all kinds of different shapes of different brushes very rapidly. I think this might be related to triggering the canvas-only mode on both windows at the same time. When trying to repro the bug for a second time, I didn't get a result that was quite as drastic, although this time I got interesting artefacts from the brush engine whenever I switched from one view to another: https://dl.dropboxusercontent.com/u/21559589/multicanvas-bug.png When trying to repro without ever invoking the canvas-only mode, the behaviour was mostly sane, but the first stroke will still always fail (and make the UI glitch around) when switching between two views. Reproducible: Always
What graphics card and driver? Here on nvidia, proprietary drivers and two monitors I cannot reproduce any issues. (I didn't expect I could: this sort of thing almost never is a bug in krita itself, it's almost always an issue with the display drivers.)
Archlinux with kernel 4.0.1, nvidia proprietary drivers 349.16, nvidia GTX 770, two 1080p monitors each connected via DVI, KWin window-manager (compositor on or off, makes no difference), ~5000x4000 px image with two layers, krita compiled from calligra/2.9 branch. I noticed that this only occurs with a pressure-sensitive tablet. Using the mouse, no glitchyness, lag or first-stroke-buggyness seems to occur.
Can you check again with 3.0? So much code changed that I'm not sure that trying to pursue this bug is still useful unless we can re-confirm :-)
Just tested with 3.0. It seems that the situation is better, but it's hard to test, as krita constantly crashes in multi-window/multi-view mode. Creating a document, creating a new window, then in that new window switching to a view of the created document, then trying to paint in both windows alternatingly makes the UI block up. As the UI blocks up, it pops open a message "Group not editable". With the mouse it does work (sorta?) and the performance seems fine then. With the tablet, the UI locks up quickly, and then trying to close the document makes the entire UI hang completely or even segfault. I'm still observing the following things, however (which of these are bugs, you'll have to make a decision on, I suppose -- but some of them are rather unexpected, like the layer switching): - when switching between windows to draw in, the preset changes (is it supposed to be that way?) - when switching between windows to draw in, even though the preset changes, the outline of the preset remains the old one sometimes, so that you end up painting with a different present than what your brush outline would suggest you are using. - the tool selected also changes (e.g. line-tool in the first window vs. brush in the other) - blending mode also changes - different layers can be selected in different windows - creating a new layer in one window breaks painting in the other, until one selects a valid layer in the other window
Yes, those sounds like bugs, all different ones. Maybe it's time you started fixing some, too :P
*** This bug has been marked as a duplicate of bug 363124 ***