[Ur] Weird behavior with dyn tags in recursive call

[Adam Chlipala]

David Snider wrote:
> I was trying to modify the tree example to be a collapsing tree and 
> when this renders the javascript ends up getting spewed out all over 
> the form. It looks like it's getting escaped or something.

There wasn't anything wrong in your code.  It was a bug in the runtime 
system, which is now fixed.

P.S.: In the future, it would be helpful to me if bug reports came in as 
more minimal test cases.  In your example, the functor, for instance, 
was entirely irrelevant to the issue.