How do I go about draging and dropping between to details listviews that are visiually full /need to scroll ?  

 

If there is room in the list I can drop from 1 list to the one with the space but if they are full I can't.

example full lists.

Hello Jeff,

Thank you for writing.  

RadListView handles the whole drag and drop operation by its RadDragDropService. The PreviewDragOver event allows you to control on what targets the cell/item being dragged can be dropped on. The PreviewDragDrop event allows you to get a handle on all the aspects of the drag and drop operation, the source (drag) control, the destination (target) control, as well as the cell/item being dragged. This is where we will initiate the actual physical move of the cell/item(s) from one listview to the target control. 

The following help article demonstrates a sample approach how to customize the drag and drop service and achieve dragging items in DetailsView from one RadListView to a target control which can be another RadListView as well. Feel free to modify it in a way which suits your requirement best: http://docs.telerik.com/devtools/winforms/listview/drag-and-drop/drag-and-drop-using-raddragdropservice 
 
I hope this information helps. Should you have further questions I would be glad to help.

Regards,
Dess
Telerik by Progress