Comment 2 for bug 1719047

I had the same problem following an in-place upgrade from Zesty+Unity to Artful. With the possible exception that my mouse pointer didn't even change to "the arrow, tempting you" when hovering over the window border.

I did an apt upgrade, an apt uninstall of *unity*, and a reboot. I can now resize snapped windows. For reference I currently have mutter 3.26.1, and libgtk+3.0 3.22.21.0ubuntu1.