DND in TreeView

[Deng Xiyue <manphiz gmail com>]

Hi gtkmm maintainers:

I'm having some problem on handling DND in a TreeView.  I tried to
handle DND with signals in Gtk::TreeModel:
Gtk::TreeModel::signal_row_deleted() and
Gtk::TreeModel::signal_row_inserted().  In most cases they work well,
except on the last row: when dragging the last row away,
signal_row_deleted() is never emitted; when dragging a row to the place
after the current last row, signal_row_inserted() gives the Path of row
0.  The test is done in gtkmm 2.14.3.

I wonder whether it is a bug in GTK+/gtkmm or I'm using the wrong
signals for in TreeView DND handling.  I'm aware of the DND example in
gtkmm tutorial, but seems to describe a general way to handle an widget
as a source/destination to coordinate with another widget, instead of a
DND within TreeView rows, or at least not an optimum way for that.
Correct me if I'm wrong.

Regards,
Deng Xiyue

(PS: I'm using gmane to access various mailing lists so it should be
safe to not CC me, but I wouldn't mind if you do so by mailing list
policy.)