Hi,

UltraComboEditor doesn't have any functionality build-in for something like this. I'd recommend that you use the ButtonsRight collection to provide your own dropdown. You could use an UltraTree or UltraGrid control on the dropdown to display the data like you have it here.

Here's another post where there's some sample code which shows you how to replace the existing dropdown in the combo with a control of your choice.

UltraComboEditor - Can I Use a Custom Control for the DropDown? - Infragistics Community