Hey Molinko!
Thanks for the fast reply. Your suggestion to use threads was the right hint over the bump! I understand your concerns about the reactiveness of the GUI, but my programm logic is very small. The level of a fluid tank is read every second and a rs-output is set/unset by it's value with a hysteresis. Also the fluid level is written to the GUI. Nothing special, most of the time my logic idles.
Edit: Ah, one thing: When I update GUI objects in my programm logic, I have to call application:draw(true) to actualize the values visible.
Thanks again!
gl&hf!