Comment 10 for bug 1243233

You're right! When the workspaces are disabled, the shortcuts overlay does appear in my laptop!

But, previously I said that the shortcuts overlay was appearing on an external monitor (bigger resolution), and I didn't disable workspaces then. I'm pretty sure the overlay was a lot bigger in the external monitor.
I bet the overlay also displays the shortcuts to manage workspaces when they are enabled, making it bigger, which would explain why the overlay doesn't appear in laptops when the workspaces are enabled.
I'll test this in a few days, then I'll add a comment to confirm if my bet was correct.

BTW, I found this bug report https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1245101 reporting what you said, Fred.