When applications change the items shown in the menubar, the global menu does not update properly. Instead of replacing the old items with the new items, it adds the new entries to the right of the old entries, with the old entries becoming no longer clickable. Trying to click on the old entries sometimes crashes plasmashell. This happens only with the global menu plasmoid. The global menu which appears as a dropdown menu in the titlebar of applications updates properly.

Till now, I have been able to reproduce this with FreeCAD (menu items change depending on the workbench selected). FreeCAD uses qt4, and I'm using appmenu-qt4 (package: https://www.archlinux.org/packages/community/x86_64/appmenu-qt4/ ) (upstream URL: https://launchpad.net/appmenu-qt )to allow the global menu to work for qt4 applications.