[AccessD] Runaway Form?

Dear List:

I have a simple bound form.  When I open it and it is (apparently) just
sitting there waiting for me to do something, the task manager shows Access
using 50% of the machine cycles (I discovered this because whenever I opened
the app the fan in the comp would fire up).

I put break points in all the modules behind the form, and breakpoints in
all the public functions to see if I could catch it doing something.  

The form is called from the Main Menu.  So in the called form Open event, I
put Docmd.Close acForm, "frmMainMenu" and the CPU use for Access went to
zero.

So It's apparently something about leaving the Main Menu form open with the
called form.  I put breakpoints in all the modules behind Main Menu.  Didn't
break anywhere. I tried putting an open Main Menu command in the called
form's exit routine, but the Main Menu didn't open. 

This is pretty plain vanilla stuff and I've never seen this before.  So I'm
kind of stumped.  Has anyone seen this behavior before or have any ideas on
how to track down the problem?

MTIA

 

Rocky