I am using 12.04 with Gnome 3.
Super + Alt + Right Click works in Gnome Classic. However, Alt + Click doesn't work with Gnome Panel.
Normally, it should bring up a way to customize the panel.
I found a solution to the problem, see: https://bugs.launchpad.net/ubuntu/+source/gnome-panel/+bug/891622
We need to run the following command in terminal: