>Let me ask you something, in most cases I am assuming that with a 50ms timer, >the timer is up before the timer-code is finished. Does that mean that the >timer-code will re-run immediately, or not until the timer-code is finished, >then it runs it again?

For sure strange things start to happen once the timer is too low (ms);
I tried to reason the how and what, but didn't come to conclusions, except for things going wrong unexpectedly.
I'm used to reset the Interval to 0 within each Timer-method, anticiptating on a parallel proces setting the Interval during the execution of the Timer-method.
I'm rather sure this helps in occasions.

Note : 50 ms for me always works okay and 1 (!!) acts stupid (I think the minimum-used is 20 now). However, this will depend on the speed of the PC !