Combo Box Selection is Blank

[Reva]

I have created a form which includes the fields [Unit], [Rate] and
[ExtendedCost] which is the sum of [Unit]*[Rate]. The [Rate] field is
actually a combo box which allows the user to select a rate from a query.
When I click the arrow for the combo box to expand, all the rates are listed,
however, when i make a selection the combo box remains blank. However the
[ExtendedCost] field still calculates. The table from which this form was
created works perfectly and the combo box functions and displays the
selection. Can anyone help?

 

[Reva]

Correction to my earlier post. The combo box consists of 3 columns -
description, rate, unit of measure. Although the bound column in Column 2,
it is now bringing in the description instead of the rate. Again the
[ExtendedCost] field is correct.