>I do have X11 forwarding configured and I don't have any problems >when working as the same user for which I logged in via ssh -Y. >But if I change the user by using su (doesn't work) or sux (works on >a local machine), Xauthorization fails.
oh wait... maybe the problem is something different? after the "su -" you also lose the DISPLAY setting which was set after logging in with "ssh -Y". you should check the DISPLAY variable before and after the su on the remote machine.
