Tunnel with automatic local port breaks x-server

While WinSCP is running a tunnel connection, any local application (eg. xterm) trying to connect to the local x-server (eg. XWin) will crash. This is because WinSCP "steals" the local port 6000 (on 127.0.0.1) which is in use by the x-server (on 0.0.0.0).

OK, it was bad choice. I'll change the defaults. This issue has been added to tracker.

Anyway, you can choose any other port manually on Tunnel tab of Login dialog.