Hi tromnek, the thread duckmango mentioned above was mine, I had the problem that the threading module wasn't even there in Poser, so I installed Python 2.2 and exchanged Poser's python22.dll with the standard Python one. This takes care of the availability of threading. I still have some issues with threads, but I suspect this is caused by the Tkinter mainloop. So if you don't need a GUI, you should be fine. BTW, does anyone know how to query if a Tkinter app has the focus or not? Martin