I have a 2 column list box on an Excel form. I'd like the user to be able to
set any value in the second column to a value in a predefined list.

What I'm aiming to do is this: when the user clicks on an item in the list
box a combo box is positioned over the item in the second column and
displayed. When an item in the combo box is selected the value in the second
column is set to whatever has been selected in the combo box and then the
combo box is hidden.

I have an idea on most of what I need to do, however I'm a little stuck on
how to position the combo box in the correct position each time. I'd also
prefer to avoid using anything other than the standard controls in Excel, and
don't have the option of using any .NET stuff.

Any suggestions would be appreciated.