Created attachment 990 [details]
Screenshot of main menu
FLTK adds a non-standard "Print Front Window" to the main menu on macOS. This is just a confusing addition that isn't really relevant for us. It should probably be removed.
Note that this is a bug as we have code that should hide this. It is also not a recent bug as even ThinLinc 4.9.0 has this issue. The code was originally written for ThinLinc 3.2.0, and last touched in bug 3865 for ThinLinc 3.3.0. So this might have been broken for years.
Also note that it works for vncviewer for some reason (when run manually, as we also have bug 3746).