SUMMARY If we use the "Global Menu Widget" and open a app like Kate, for example, the menu shows in the widget, but if we open a Kirigami app like Neochat, for example, the menu doesn't show in the widget. STEPS TO REPRODUCE 1. Add the global menu widget in some panel 2. Open Kate and see that menu appears in the widget 3. Open Neochat and see that menu doesn't appears in the widget OBSERVED RESULT Kirigami applications doesn't show menu in the global menu widget EXPECTED RESULT Kirigami application showing the "main menu" (the one from the hamburguer button) in the global menu widget. SOFTWARE/OS VERSIONS Linux: Arch Linux 5.13.10-arch1-1 (available in About System) KDE Plasma Version: 5.22.4 KDE Frameworks Version: 5.85.0 Qt Version: 5.15.2
This is because those apps don't have any menus to show. Some actually do, like Elisa--because they have implemented a menu structure. You would need to ask the apps in question to in fact implement a menu structure in the first place.