Blocking GOM VPN

Hi,

Just wondering if anyone has any experience in blocking traffic from the GOM VPN browser plugin?  I've done some testing and even with SSL inspection enabled and every single FortiGuard category blocked, I'm still able to get full web access with the plugin installed.

I assume it just tunnels everything over HTTPS but I'm surprised that it's not blocked by the 'Proxy Avoidance' category.

Thanks,

Matt