The key is definitely working:

xev says:
KeyPress event, serial 36, synthetic NO, window 0x1a00001,
root 0x2f5, subw 0x0, time 2082267546, (-425,-539), root297,358),
state 0x0, keycode 133 (keysym 0xffeb, Super_L), same_screen YES,
XLookupString gives 0 bytes:
XmbLookupString gives 0 bytes:
XFilterEvent returns: False

xmodmap says:
xmodmap: up to 3 keys per modifier, (keycodes in parentheses):

shift Shift_L (0x32), Shift_R (0x3e)
lock Caps_Lock (0x42)
control Control_L (0x25), Control_R (0x69)
mod1 Alt_L (0x40), Meta_L (0xcd)
mod2 Num_Lock (0x4d)
mod3
mod4 Super_L (0x85), Super_R (0x86), Super_L (0xce)
mod5 ISO_Level3_Shift (0x5c), Mode_switch (0xcb)

The thing I don't quite understand is the two cases of Super_L, one as 0x85 and another as 0xce. Is this normal?

I can't get rid of it, not even with .Xmodmap:

clear Mod4
keycode 133 = Super_L
add Mod4 = Super_L Super_R

Any ideas?

Many thanks,
Biff.

Biff, I encountered a similar problem binding 3d desktop functions to key sequences in KDE. After much head banging, I discovered that not all keyboards are created equal. I had recently switched from a run of the mill 101 key el-cheapo PC USB keyboard to an Apple Aluminum Keyboard. KDE has a config mode that alters the functions of the special keys on Apple keyboards, making them more compatible with traditional 101 key PC keyboards. After fooling around with these settings for a while, I happened across a configuration that worked for me. If your using a non-standard keyboard this could be a similar problem. I'm not familiar with Fluxbox, but I suspect there is a similar setting somewhere, if not in the GUI, perhaps a manual edit of the config files is in order. Anyway, that's my best idea on it. Best of luck and let me know how it goes.

Hi DarkWolf,

Well, I got it working on another computer, with another keyboard, so at least I answered my own question about whether the duplicate Super_L is causing the problem.

I thought it was a pretty standard UK Dell keyboard, but next step is to try a different keyboard with the machine that doesn't work, as you said.

thanks,
Biff.