SUMMARY In case you haven't noticed yet, resizing the left panel of Okular (which contains preview images, annotations, bookmarks, the outline, and layers) is super laggy since quite some time, I believe at least since two stable releases. STEPS TO REPRODUCE 1. Open Okular, ideally with a PDF file. 2. Expand the left panel (F7), in case it is currently hidden 3. Try to resize the panel. OBSERVED RESULT Resizing the panel is jerky. EXPECTED RESULT The panel should resize smoothly, like any other panel does. SOFTWARE/OS VERSIONS Operating System: KDE neon 5.22 KDE Plasma Version: 5.22.4 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.3 Kernel Version: 5.11.0-27-generic (64-bit) Graphics Platform: Wayland Processors: 4 × Intel® Core™ i5-3570K CPU @ 3.40GHz Memory: 7.2 GiB of RAM Graphics Processor: Mesa DRI Intel® HD Graphics 4000 ADDITIONAL INFORMATION I'm surprised that apparently no one has noticed the issue yet? It's super obvious.
Ping. :)
Bug 427913 mentions config file writes on any movement as possible cause, so maybe users with faster disks don't experience this as much... *** This bug has been marked as a duplicate of bug 427913 ***