I recently upgraded to Ubuntu 13.10 64bit and Receiver Version 188.8.131.526735. I use the Receiver to connect to a remote virtual desktop hosted by my employer. Soon noticed that the ctrl key is sticking. The only workaround I have found is to reboot the virtual desktop and reconnect. This problem is making the product nearly unusable. This problem was not occurring with my previous version - Ubuntu 13.04 and Receiver 12. I noticed a comment by Michael Eitelwein (http://discussions.citrix.com/topic/335516-alt-key-stuck-still/) reporting the same problem. Any updates, fixes, or workarounds for this problem?