keyboard shortcuts with mod4 no longer settable in 2.16

[Allan Gottlieb <gottlieb nyu edu>]

I use mod4 (and shift-mod4) for my keyboard shortcuts
(for example <Mod4>F1 shows the panel menu).

This continues to work.

But I cannot add new ones using gnome-keyboard-bindings, which I how I
added all my existing shortcuts in previous gnome releases.

Now when I press the mod4 key, the shortcut is immediately bound to
Super_R instead of waiting for me to type in the 2nd key.  Mod4 has
essentially lost its function as a modifier and is just a key.

I would be happy for a text based tool, but I could not find anywhere
in gconf-editor to change/add keyboard modifiers.

Thanks in advance for any help.
allan