I just upgraded to Ubuntu 20.04 LTS Focal Fosa and I've lost the use of the Super key to bring up the search window with the Spanish and Belgian keyboard layouts (2nd and 3rd layouts). The Super key is still working with EN (1st language in the list). There's a bug already being worked on (see comment by @to-do below)
I've tried adding it to the Keyboard Shortcuts in settings but it is not recognized.
This happens both with my laptop keyboard and an external keyboard. The computer is a Dell Precision 5520. There was a firmware upgrade during the upgrade from 19.04.
As a workaround I'm using Super+S , but I would prefer to have just the Super key working in all layouts as before.
Do you have more than one keyboard layout?
There is a bug with the latest Gnome that makes the Super key not function with the second and forth keyboard layout in the list.