Yes, that's probably just the desktop notifications rather than overlay rendering.
The problem is not the notification itself. The problem is Steam raising notification while I'm playing the game in full screen mode. Please reopen.
There is no concept of exclusive fullscreen on Linux and Steam doesn't know what a particular game might be doing. You can disable friend notifications or unfollow groups that you'd like to stop receiving event notifications for.
So you mean to say glutFullScreen is a bogus? Or there's no sane way of disabling all notifications during play somehow not hindering user experience here?
I'd expect the compositor of the DE would have control over this behavior if there is any control at all, not steam.
Nothing extracted yet.
Fedora 23/Gnome/radeon oss
Steam client version: 1.0.0.51-1.fc23
Opted into Steam client beta?: y
In steam settings UNCHECKED "Enable overlay". In Team Fortress 2 properties UNCHECK "Enable overlay". Playing Team Fortress 2 full screen mode native client.
Steam group events still cause messages to pop-up. Gnome desktop reacts by drawing a notification window may be? Desktop fall though at the top of the screen for a couple of seconds.