Is there a way to do this?
No. Using the arrow selects an item on the list.
It's been messy code so far and I am trying to clean it up, but I figured out that I can always capture the key press -- allow the item to be selected, but not fire the events that make it look like it was selected (such as populating the rest of the row in the grid with items related to the drop down).
Feels kind of like a hack, but hey it works.