For maximized windows, titlebars cannot be used to reposition or
scale the window, so if an application does not use it to convey
useful information (other than the application name), the screen
space occupied by titlebars could be put to better use.
To account for this use case, a setting for requesting that windows'
titlebars should be hidden during maximization has been added to
GTK+, add support for this in the window manager.
https://bugzilla.gnome.org/show_bug.cgi?id=665617
9729a99ec5