How can I turn on Wobbly Windows on Ubuntu Mate 18.04?
First of all you need to switch window decorator to Compiz in mate-tweak.
Then install CompizConfig Settings Manager
sudo apt install compizconfig-settings-manager
and launch it with ccsm, confirm usage, enter wobbly in search bar, click checkbox near it and confirm disable of Snapping Windows plugin:
and enjoy:
You do not need compizconfig or mate-tweak. Just Open Ubuntu Software Center, then search for 'Wobbly Windows' and install it. Click on 'Extension Settings' scrool down to Wobbly WIndows and keep it ON.
There you go ! It works for me.