I changed the keybinding to
Show the activities overview in the panel
System Settings / Keyboard / Shortcuts to
Shift-ESC, but the left-meta or left-windows key is still bringing it up.
How do I disable that binding?
gconftool -s /apps/mutter/general/overlay_key -t string "Super_R"
worked (after shell restart) for me. Instead of
Super_R feel free to put name of any key which doesn't exist on your keyboard.
In recent GNOME use:
gsettings set org.gnome.mutter overlay-key ''
and to restore the default keybinding use:
gsettings set org.gnome.mutter overlay-key 'Super_L'
borrowed from here.
This worked for me: At Tweak Tool > Typing > Alt/Win Key behavior, select Meta is mapped to Left Win, this replaces the Left (but not right) Win key with a dummy alt key which otherwise works like the Win key but doesn't toggle Activities (and I saw that from Florence virtual keyboard).
Original answer is here.