Drag&Drop

when drag&drop betweem two treegrids, if the drop point is the tree column with split style, the first tree column and second column will be staggered. How to deal with this?
before:              column1(split)     column2       after:              column1            column2
                row1   cell11                 cell12                  row1      cell11               cell12
                row2   cell21                 cell22      d&d --> row2      cell21               cell22
                row3   cell31                 cell32                  row3      cell’new’           cell32
            

Current version of grid (1.3) doesnt support d-n-d in split mode.