SUMMARY Today an update landed after which all the menu bars for all applications disappeared. And none of the applications appear in the taskbar. When I choose the Wayland Plasma as a login option, then menu bars and the taskbar work fine. This bug appears also for a new user I just created. SOFTWARE/OS VERSIONS Operating System: KDE neon 5.20 KDE Plasma Version: 5.20.0 KDE Frameworks Version: 5.75.0 Qt Version: 5.15.0 Kernel Version: 5.4.0-51-generic OS Type: 64-bit Processors: 8 × Intel® Core™ i7-4770 CPU @ 3.40GHz Memory: 15.5 GiB of RAM Graphics Processor: Mesa DRI Intel® HD Graphics 4600 ADDITIONAL INFORMATION
Sounds very much like bug#427639... *** This bug has been marked as a duplicate of bug 427639 ***