I am sorry to tell, that I had to delete the former post. It was dangerous to alter the class SessionManager.
Therefore we have converted the translated text into a global variable instead for a session. This result in much smaller left over files that is taken by the carbage collector.
The reason for the left over session files is that we for security reasons have to regenerate session id's.
The changes will go to next minor release and the HG repository will be updated soon.
/Joe
