Thing you learn when you're just playing around

While my Unity build-settings specify that this mini-app is supposed to run in the background, I note that on my system the elapsed time doesn't seem to change (much) when I switch tabs (although I can still hear the clock clicking once every few seconds).  For what it's worth, I am using frame updates to drive the logic updates at this time.  I guess I'll need to drive the hour/minute/second hands off of system time, rather than internal variables.