Hi, quick heads-up for anyone maintaining applications which also target non- Plasma shells (X-based, no issue with wayland-based systems):
TL;DR Make sure to have "StartupWMClass=myapp" in the (main) application desktop file if both WM_CLASS properties of the application window do _not_ match in lowercased version the basename of the application desktop file. This enables non-Plasma shells map the application windows to application menu entries (e.g. on the panel) Your (Qt/KF-based) application should also properly integrate with non-Plasma shells? If so, here another thing to check if you haven't yet: 1. start your application 2. start "xprop WM_CLASS" on the commandline and click the app window with the cross mouse cursor Example output for Okular: WM_CLASS(STRING) = "okular", "okular" 3. check the basename of the (main) desktop file of your application (the one which matches the desktop file name you register to the QApplication, either via KAboutData::setApplicationData() or directly via QGuiApplication::setDesktopFileName(), see also result of "xprop _KDE_NET_WM_DESKTOP_FILE") Example for Okular: org.kde.okular This mismatch is a challenge for non-Plasma shells. We need to help them here over it, by adding another line to the application desktop file, which matches the second entry (or the first, seems both supported) of WM_CLASS. As this is what they/some use then for mapping windows to applications. Example for Okular: org.kde.okular.desktop gets a new line: StartupWMClass=okular Once this is done, Gnome Shell & Co. should properly map windows/running instances to launcher entries. BTW, while you touch the desktop files, you might also want to change keys "X-KDE-StartupNotify" to "StartupNotify", given this key is official part of the desktop specification since >10 years. It's not totally clear which shells support the official key properly besides Plasma, but if they start to do, better start to help them now already. Cmp. https://specifications.freedesktop.org/desktop-entry-spec/desktop-entry-spec-latest.html#recognized-keys Background: While in wayland-based systems the desktop id (i.e. the name of an application's desktop file name) is used by design to map windows to registered applications, there is no same thing for X-based systems. While there was a proposal to use also something desktop-file-based by KDE developers, this was not picked up by the full XDG team, only Plasma/ KWindowSystems implemented support for this (cmp. also the "_KDE" prefix of the "_KDE_NET_WM_DESKTOP_FILE" property set on windows of Qt-based apps running with the Plasma QPA). Possibly everyone looking forward to "wayland fixes it" and not investing more resources into the X-based solutions. So applications have to go and embrace what works on such systems. See also related discussion with some insights: https://bugzilla.redhat.com/show_bug.cgi?id=1234734 Disclaimer: all above written as result of research in last 2 days, small chance I missed a detail, so best test before applying any related changes. Cheers Friedrich
