For instance, in dosbox or wine apps configurated for fullscreen. This is highly annoying.
I've noticed that apparently Unity (which i don't use) doesn't have this complaint, probably since Unity is using compiz and not mutter.
From the link above i infered that it's related to the feature 'unredirect_for_screen' which is a property to not shape the graphics output when in fullscreen mode. However, allthough mutter has a commit with the same capacity since 3.1 (my version is 3.6 atm), it has no dconf setting for enabling it that i can see. I can only infer that it's done automatically when a app requests fullscreen. The question is then, why doesn't it remove the top panel (ie; be 'unshaped') in both wine and dosbox while 1 indicates that it's not a problem in unity+compiz?
Please do not answer with one of the extension hacks that removes the top panel. I do not want to remove it except in the fullscreen case (though the wine 'virtual desktop' case is problematic)