See if tab works now. If it doesn’t, then something might be intercepting the Tab keystroke (it works for you in Krita?). You might also try another desktop environment if you already have another one installed (usually you can select one before you log in). Hope this helps!
FullscreenAutohide has ‘Tab’ mapped to it. Mapping ‘Tab’ to Fullscreen doesn’t do anything.
EDIT - Krita’s “Fullscreen” in this case is what they call “Canvas Mode” and is the equivalent of going Fullscreen, then hiding the menus in MyPaint. They do have a “Fullscreen Mode”, which is called with ‘Ctrl+Shift+F’, which does the same thing as MyPaint’s ‘F11’
edit. So if Tab was still mapped to the FullScreenAutoHide-- that means you never successfully made the assignment for Tab=Fullscreen… hmm… So Tab works fine when you’ve already entered full screen; it hides the tools panels, right?
Is it only Tab=Fullscreen that is broken? That is, can you map Tab to something else like zoom or increase brush size, and does that work?
If nothing else, try remapping FullScreenAutoHide to something else, and then edit the file as I mentioned before and just set it. Let’s see if that at least is a work around and let us know where the error lies (possibly during assignment).
Could you try these again with the mypaint-git package in the AUR(1.3.0.alpha.r4847.70ce73d9)? In my testing, I was able to reassigned Tab key, however if you just reassigned the FullscreenAutohide to another key map, tab key still works as well.
Also far warning, if you install gimp-git from the AUR, it will conflict with mypaint-git. They use a different version of libmypaint(1.3 instead of 2.0 with mypaint).
It’s working on my end(Tab=fullscreen, F11=FullscreenAutohide) so all I can say is do a complete reinstall of the mypaint-git package from the AUR. Also delete the config files as well. Hopefully that will clear the settings up to allow you to assigned Tab to fullscreen.
BTW, I’m on Gnome Shell with Antergos if that helps.
No sadly, as of right now we don’t have that functionality. You can thank the GTK3 devs for removing the ability of easily doing that sadly… @bleke did submit a Feature request for it though, so go ahead and vote for it. Also add your thoughts as well: Hide Controls in Windowed Mode
I’ll also fill out a bug report on MyPaint Github repo when I have time about the funky behaviour of the Tab key.