Does anyone know what triggers this error?

Can't enter break mode at this time

Help says:
"... A change was made programmatically to the project using the
extensibility (add-in) object model. This prevents the program from having
execution suspended. ..."

What sort of thing triggers this? I have no idea what the "extensibility
object model is" and what I might have done to cause it to be used
(whatever it is).

--
eugene