Timer events are placed only in the application event queue if that queue is empty and
the application is idle. Windows does not place timer event messages in the application
event queue if the application is already busy. If your application has been busy and has
missed several timer event messages, Windows places only a single timer message in the
event queue. Windows does not send your application all the timer event messages that
occurred while your application was busy. It doesn’t matter how many timer messages
your application may have missed; Windows still places only a single timer message in
your queue