Xcode 4 - key key for key binding, maybe for you?

Hi guys, in xcode 4, I cannot bind the “Shift Right” command to the key option+taband “Shift left” to option+shift+tab. I use textmate and these commands are bound like that, so I need the same setup in xcode 4 ... But for some reason it adds the command key to my binding! therefore option+tabreplaced byoption+command+tab

The quick fix I found was to overwrite the binding in the system settings, but was wondering why Xcode would not let me use my binding?

thank!