SUMMARY: If XDG_CURRENT_DESKTOP set e.g. to "gnome", clicking Alt makes konsole to stop accepting text input. If you press Enter afterwards, it makes a menu appear, which suggests that konsole refocuses on its menu. STEPS TO REPRODUCE 1. Run `XDG_CURRENT_DESKTOP=gnome konsole` 2. Press and release Alt key 3. Type "test" OBSERVED RESULT Nothing happens. EXPECTED RESULT "test" should appear in the shell SOFTWARE/OS VERSIONS Linux/KDE Plasma: unused, it's i3 WM instead. KDE Frameworks Version: 5.52.0 Qt Version: 5.11.2 ADDITIONAL INFORMATION "Settings → Configure Konsole" has a "Enable menu accelerators" unchecked, which probably means Konsole shouldn't ever switch focus to its menu.
Ok, never mind, I found this workaround in somewhat irrelevant thread: Install qt5ct, maybe run it to configure, and then set an environment variable QT_QPA_PLATFORMTHEME=qt5ct. This makes the problem to go away, and while this is not directly relevant to the bug, this comment suggests this variable must be set nowadays for Qt apps to work correctly¹ 1: https://bugs.kde.org/show_bug.cgi?id=344149#c5