Compose key mapping does not work in Fedora 18?

edit

After upgrading to Fedora 18, my Compose key seems to be non-functional.

I have the keyboard layout set to the default English/US, and in System Settings → Keyboard → Shortcuts → Compose Key = Caps Lock.

The Caps Lock key seems now to be totally dead; it neither toggles capitalization, nor does it work as a Compose key.

Strangely, xmodmap shows this line:

        66         0xff20 (Multi_key)      0xff20 (Multi_key)      0xff20 (Multi_key)      0xff20 (Multi_key)

If I change Compose Key = Disabled, that changes to

        66         0xffe5 (Caps_Lock)      0x0000 (NoSymbol)       0xffe5 (Caps_Lock)

... and that does work; so keysym=66 seems to be the right place, and Multi_Key (Compose) is being bound to it.

Do I perhaps have to choose a Compose key table to load? (locale=en_US.UTF-8 and /usr/share/X11/locale/en_US.UTF-8/Compose exists with more-or-less the contents I would expect to see)

The same effect occurs on both built-in keyboard (laptop) or USB keyboard.

I have also attempted to use the Tweak tool to turn off Caps Lock, but that seems to have no effect.

Am I just "doing it wrong?"