Right now TestComplete supports this control as a Tree. However with the control containing columns(it is a hybrid of Table and Tree controls), getting all the column details for a specific tree item is very tedious. It would be very helpful if this control is supported as a Table as well.
Attaching the control's documentation:
Upon looking into this documentation found that GetItems method can used to retrieve all the root level tree-items. I think TestComplete can use this method in supporting this control(Like how its supporting JFace TableViewer).
Attaching the sample screenshot of the control:
TreeViewer with columns