I am using x2go client v18.104.22.168 (but saw same issue with 22.214.171.124).
I start a connection to a Linux host (Knoppix v7.0.5) using LXDE session type and fullscreen display. Client host is Windows 10.
After the fullscreen client is displayed, I cannot access the x2go menu bar (at the top, center of the window, owned by x2go). I move my mouse to the top, but it does not appear. The alt keys for switching out of fullscreen mode do not work either. Only method I have found that works is Windows alt-tab key.
This change in behavior just started recently, and AFAIK, I had not made any changes to client or host x2go. I did upgrade to latest x2go client (to see if issue was fixed), but that did not change the behavior.
I have tried this from 2 different client hosts (other was Windows 7), and 2 different target hosts. All behaved the same.
I would have sent the configuration file, but it is not obvious what file that is. Would be useful if you added more details on how to find/identify this file.
Is this a known issue? Is there a workaround?