I'll take a look through that later, just to see what all is in it.
But I figured out the problem. It was related to the fact that I was already using an EntityJig, and I tried to save some processing by using a calculation from the EntityJig. The call to PointMonitor was happening before the required data was being updated by the EntityJig, so that wasn't working.
I redid the code, so that the PointMonitor handler performs the required calculation, and it works fine now.
In the process, it seems as though the EntityJig is no longer necessary. I was having problems with the EntityJig, in that I wanted to draw a series of objects, and I couldn't figure out any good way of doing that with a Jig. However, it seems quite easy to do it with PointMonitor instead. So I suspect I may want to redo this code, and possibly eliminate the Jig entirely.