I have implemented Debra Dalgleish's terrific combo box validation
macro (http://www.contextures.com/xlDataVal11.html), but have run
across a problem. I want to limit the values accepted from the combo
box to the validation list.

I have attempted to make this happen by changing MatchRequired to True,
but this doesn't seem to be working. The only solution I found was to
change the style to "2- fmStyleDropDownList," but I am dissatisfied
with this option as it seems to preclude the user from Escaping out of
the list and leaving the value blank.

Ideally, I'd like for Excel to evaluate the value in the combo box and
provide a specific error message to the user if they have entered an
invalid choice. I tried to implement a TempCombo_change macro, but it
doesn't seem to be called, perhaps because it is a temporary combo box
(cboTemp) that is called by the BeforeDoubleClick Event.