Cannot use super+space as a shortcut in XFCE

view story

http://askubuntu.com – I moved from kde to xfce, and I've found that I cannot use super+space as a keyboard shortcut (applied via the xfce keyboard settings program). My main concern is that I use that shortcut to open up my drop-down terminal (which is currently the xfce4-terminal using the --drop-down option. The catch so far has been that I can use yakuquake with this keyboard shortcut, but not xfce4-terminal. (HowTos)