Breakpoints being ignored

[Mark Powell]

Breakpoints are not being recognized all of a sudden.  Something
do doubt is corrupted and I'd be interested in knowing if there is a clean
fix.

Test case:  I create a brand new stack, with a button scripted

on mouseup
  answer "1"
  breakpoint
  answer "2"
end mouseup

I get the two answer dialogs, but without the script breaking at the
breakpoint.

Any tips appreciated!

Mark