Another approach to test if Draw() gets called repeatedly is that, you can implement a simple timer class & call Notify() method from that timer after few secs repeatedly & see if Draw() then gets called or not. Start this timer as soon as container is drawn & do not initiate a phone call. In the notify() method pass some hard-coded int values from timer itself & see the behavior. This may confirm it the irregular behavior of Draw() is due to call or something else.