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Installed Ubuntu 12.04 64bit today, switched to Gnome Classic (no effects) and there is one thing that makes me crazy: I can't assign Super+L to Lock Screen function!
I go to System Settings -> Keyboard -> Shortcuts -> System, then I click on Lock Screen and press "Super + L", it appears in the list but when I press it again it doesn't work.
If I set it back to Ctrl+Alt+L it works again. Actually, I tried to set it to different Super + ?? combinations, and neither of them work.
if I assign Super+L to so other command, like Start Terminal, it works.