5th October 2016, 16:41
(5th October 2016, 13:56)leszek Wrote: It might be a caching issue.
Try going to ~/.cache/ and removing the activityswitcher_wallpaper_preview.kcache file and see if after a relogin it creates correct thumbnails again. (Maybe need to switch to the activities for it to refresh the cache)
Thanks, but it did not help. After deleting that file & logging out/in, KWin/Plasmashell did not properly recreate the desktop [IMO this was unrelated to deleting that file; for the past couple of days Plasmashell has been a bit unstable again with a few crashes], & before i then fully rebooted, i noticed that the Activity Manager previews were still black, & that file had not been recreated in .cache. After rebooting,my desktop was good again, but still the Activity Manager previews were black, & that file had not been recreated in .cache. Bummer.