Not having much luck today with Infragistics controls - must be me :)
Simple WinTree in OutlookExpress mode - columns and nodes are populated in code. Can't figure out why expansion indicators are on the right side. How do I move them to the left of the first column? BTW - expansion works fine but looks crazy.
If you don't explicitly set the CanShowExpansionIndicator property on the column that you want to display it, the first column of type string is the one that shows it. This is in emulation of OutlookExpress; they seem to always show it in the subject column, even if you move that column from the leftmost position, so we (sort of) did the same. In your case you want to set the CanShowExpansionIndicator property to true on the 'ID' column.