Hi all,For GNOME, this indeed did the trick to enable the APPLE key to also perform as ALT key:
Applications / Desktop Preferences / Keyboard (Preferences) Tab: Layout Options: add "Alt and Mete on the Alt keys (default)."At first it only worked followed by an ENTER to get the same result as an ALT-TAB, but next time I booted the machine this worked fine.
Thanks, Pander