QSystemtrayicon doesn't show icon with example built with 5.1.1 but does when built with 5.0.0

I'm suffering this too. In 5.2 beta i get no systray icons. Built with 5.0.0 they're fine in mint cinnamon or mate.

just gone back through qt versions to regression test. The change happens between 5.0.2 and 5.1.0 if that's any help tracking down the source.

also when running mint cinnamon, if you turn on 'looking glass mode' when running against 5.1.1 you get the following message in the errors tab which i think sheds a little light on it....

Adding systray: <application name> (1x1px).

Sure enough if you can find the exact pixel and right click it you can get the context menu to appear.

Against 5.0.2 it shows a different message:
Adding systray: unknown (22x22px)

so it appears it adds a single pixel item to the tray in 5.1.0 and above.

Hope that's some use,

Rich