We are currently upgrading an application to run on ubuntu 18, and we are struggling with the differences on the multimonitor fullscreen handling with different desktop environments. In Ubuntu 16.04 (unity) wasn’t a problem at all.
We are starting the initial window fullscreen , with the options of multimonitor true and decorated false, and we are using the nightly builds from two days ago.
Until now we have quickly tried different desktop environments, with mixed results.
Gnome: Multimonitor fullscreen doesn’t seem to work, the application only renders in the launch screen. Also the docks seem to have a reserved space and while you can hide them, you cannot render on top of them.
Gnome flashback: The application starts fullscreen, but top and bottom bars seem to reserved on the first screen only, second screen renders properly.
openbox: The full screen command starts only in one screen, as with gnome. Also seems a little bit buggy (the screen doesn’t clean out of openframeworks), and the last commit in their git is from 2015, so seems abandoned.
MATE desktop: Again the top and bottom bar seems to be reserved. While the full screen is more or less working, the desktop background shows anywhere that you are not painting, and displace the application by the same amount as the height of the top bar.
We are open to suggestions on desktop environments or other possible approaches to try (multiple not decorated windows for example).
(updated with some pictures of tour tests)