Some apps like Gnome Tweaks or the terminal do weird things with their borders. That black square in the Gnome Tweaks title bar does actually behave as if it wasn't rendering anything, and the terminal only has title bar, but no resizing is possible.
The version of Gnome is 41.3, and gtk3 1:3.24.31-1 on Arch Linux.
Some apps like Gnome Tweaks or the terminal do weird things with their borders. That black square in the Gnome Tweaks title bar does actually behave as if it wasn't rendering anything, and the terminal only has title bar, but no resizing is possible.
The version of Gnome is 41.3, and gtk3 1:3.24.31-1 on Arch Linux.