I did a google search and saw that this had been reported about 2 months ago and Oleksandr Shneyder had found the cause and built a "patch" which you can read about here:
https://github.com/FreeRDP/FreeRDP/issues/465
Did this patch ever get applied to the newer x2go server/client as it seems the problem still exists?
-- Dipl.-Ing. Moritz 'Morty' Struebe (Wissenschaftlicher Mitarbeiter) Lehrstuhl für Informatik 4 (Verteilte Systeme und Betriebssysteme) Friedrich-Alexander-Universität Erlangen-Nürnberg Martensstr. 1 91058 Erlangen Tel : +49 9131 85-25419 Fax : +49 9131 85-28732 eMail : struebe@informatik.uni-erlangen.de WWW : http://www4.informatik.uni-erlangen.de/~morty