Chip,

Thanks for the clarifications.
The really frustrating thing is that 1) the ID #s for the controls don't
seem to be exposed anywhere in the API (or at least not in the Excel GUI),
and 2) the behavior of the controls with/without being linked to a worksheet
cell is not clearly documented anywhere that I could find.
Of course, the cute excel xlON/xlOFF constants and their nifty,
not-exactly-intuitive values doesn't exactly help avoid any confusion any
either (it wouldn't be so bad if those constants were enums for the .value
property, but apparently that was too obviously self-documenting a situation
to hope for).

Do you know if anybody's made anything like a comprehensive
document/whitepaper/website/guide to "The Proper care and feeding of Excel
and ActiveX controls in both Userforms and on Worksheets."?
I could also easily imagine the need for a similar set of guides/documents
for the multitude of SHAPE objects (_not_ counting the controls). One
specific question I have is this: where is there a document that lists all
the various valid Adjustment points for the various autoshapes? ....or is
there no such animal anywhere?