For gnome-shell, this has worked for at least the past year. Probably longer.
By "this" I mean selecting gnome-tweak-tool > Windows > Window Action Key = Alt works. The fact that Alt is not the default is a different issue. See bug 1713650 instead. ** Changed in: gnome-shell (Ubuntu) Status: Confirmed => Fix Released -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1299836 Title: Alt+mouse move doesn't drag window any more To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1299836/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs