Unable to reproduce on macOS 10.14.5, MacBook Pro Mid 2012, Intel HD Graphics 4000, works fine with everything accessible.

Is there anything I can do to test that? It is not a machine with a real GPU, just an Intel HD 4000.

The earlier Ubuntu test was on another machine running 18.04.2LTS, but for completeness, I just formatted the machine running Fedora 30 and installed Ubuntu 19.04 on it, Blender its "Toggle Window Fullscreen" performed flawlessly.

I grab Blender 2.80 beta daily and yes, three or four version back it worked fine.

Are your popup menus and drop down menus from the menu bar transparent by any chance...? Then it could be related to UI graphics glitches on macOS with Intel HD 4000...?

In T65383#696221, @Brecht Van Lommel (brecht) wrote:

It's made a bit more complicated by the fact that de0cae29cf751 added additional fixes on this commit, so 77f5210f2233 by itself is already known to be wrong, it's the combined change that needs to be debugged.

This is the exact same problem as T65383, where a "Load Factory Settings" unfortunately doesn't change things. On a cleanly installed macOS machine with just Buildbot daily Blender 2.80 beta's installed.

Here you go:

On Blender 2.80 (sub 72) things were fine, didn't download sub 73, so can't tell when the UI artifacts got introduced. Nothing else changed on the machine except for a newer daily build of Blender.

Then I get this:

Tried the same buildbot version on another machine under Ubuntu 18.04.2 LTS and there the UI artifacts don't appear, just the macOS version (10.14.5)

That would be?