I'm defintiely missing something obvious here. Do I have to manually do something when the user types in the combo box or selects an item from the list (like add the value property into the combolist) in order to get it write what is typed in to the underlying grid's controlsource?

Yes, you do. If The user types something in that is not in the combo's internal list, you have to take action to add this item and then requery the combo.

Anything typed in to the combobox just disappears as well as anything selected from the list.

I would expect this to happen when the user types somethign in that is not in the combo's list. However, when you select an item that is in the combo's internal list, it should work. The fact that this combo goes blank tells me that there is a mismatch between the grid column's ControlSource and the combo's internal list.

It would seem that dropping a combobox on the grid, even if the list were empty, that anything typed into the combobox would save the data just like as if it were a textbox.

That may be what you expect to happen, but that is not the way it works < s >. Why don't you take a look at some of the sample forms that are included with my presentation. They all work and may help to point you in the right direction.