When Does an Open Stack Not Send openStack?

[Dan Shafer]

Here's a puzzler for you.

My app mainStack does some stuff, gets some data from the user and then 
has a line:

go stack "newStack"

The newStack stack has an openStack handler that initializes a bunch of 
things. That handler was working fine. I made a catastrophic 
improvement (one of my favorite pastimes) and suddenly the 
initialization just stopped working. I debugged and found the openStack 
handler in newStack was just never being invoked.

Now, I created a preOpenStack handler in newStack to see if that 
message was being sent. It was. Which confused me even more.

So Ro Nagey and I were IMing about this and he said this is a problem 
he's seen before. He suggested that I add a preOpenStack handler in 
newStack and use it to explicitly send openStack to newStack. Guess 
what? That worked.

But why? Under what circumstances should the openStack message not get 
sent or handled?  What could I possibly have done wrong?

There's no lockMessages set anywhere and I just can't imagine what else 
could cause this.

Any thoughts? I'll go with the kludge for now but I'd sure like to 
understand what happened.

Dan