This patch primarily is aimed at applications using libappindicator. For example:
- Steam
- Discord
- Deluge
libappindicator doesn't provide functionality for raising an application, but only a context menu. Since it also doesn't even provide the corresponding DBus method, we use the resulting error to try to display the context menu instead, which matches the behaviour on Unity and Gnome.
https://www.gamingonlinux.com/forum/topic/2519
https://bugs.kde.org/show_bug.cgi?id=375351