I have not been able to launch startx successfully (remotely), though I can launch it on the local box directly. I think that my ssh client is configured correctly, which makes me suspect that the problem has something to do with inadequate libraries on the Cygwin box. (For example, if I shell from the local Linux box back to itself, I can run startx successfully.) I believe this suggests that if the remote box had the correct software, the X11-forwarding would work correctly. Does anyone have any brainstorms?