ext-dnd5 throws error for draggable column headers

[mar10]

This happens, when a column header (or other non-node) is marked draggable.
FT registers a handler for all drag events inside the container, but In this case no node can be found for the drag source.
First reported here: https://stackoverflow.com/q/53338682/19166

[tstuempfig]

Hi,
what do you think about extending the dnd5 plugin with column movement?
i made some quick hack brute force edits to enable my own ondrag and ondrop handler for the column headers. (see attached unified patch)
I could think of some callback function to be called when a drop happend on column move. The plugin implementer user could then write the changed column orderinformation somewhere accessible by the columnrender callback.

ft_bruteforce_edits.zip