I have KWIN enabled with desktop effects (OpenGL + vsync). Reproducible: Always Steps to Reproduce: 1. Open gwenview on a large photo (4k+ resolution). 2. Go into "Configure Gwenview" 3. Enable software or OpenGL animations. Actual Results: After that, gwenview loses vsync with the desktop. Panning photos causes the photos to tear badly near the top. Expected Results: gwenview should have animations and still retain vsync with the desktop. Workaround: Turn off animations in gwenview.
Can't reproduce with Gwenview from git master and recent KWin. Please let me know if you still can.