Challenge: Fix the bug:

[tombernard]

After you get your Configure Die sheet working, select a die and configure it for a high number of rolls, say 200 or greater. Then double click the die to start it rolling. As soon as the die starts rolling, double click it again. And again. And again. Now the die will never stop rolling.

The bug fix is simple once you understand what’s going on.

[tkrajacic]

I have brought this up here: http://forums.bignerdranch.com/viewtopic.php?f=535&t=10460
but this is an ugly hack that just hides a fundamental approach to using the timer in this example.