Changes

In case <code>$DISPLAY</code> is not set, make sure that X forwarding is enabled in <code>sshd</code> config inside VE. In most Linux distros sshd configuration is stored in <code>/etc/ssh/sshd_config</code>. You should set parameter <code>X11Forwarding</code> to <code>yes</code>. Also VE should contain <code>xauth</code> package, thus install <code>xauth</code> if it is missing(in Debian this is part of the xbase-clients package). After that, restart your sshd daemon: