Make the column drag code a bit more robust (still scary, though).

Make the column drag code a bit more robust (still scary, though).

Sat Aug  7 01:26:08 2004  Matthias Clasen  <maclas@gmx.de>

	Make the column drag code a bit more robust (still scary,
	though).  (#106992, Christian Biere)

	* gtk/gtktreeview.c (_gtk_tree_view_column_start_drag): Assert
	that cur_reorder is NULL here.

	* gtk/gtktreeview.c (gtk_tree_view_button_release_drag_column):
	Reset cur_reorder to NULL, and only hide drag_highlight_window
	if it exists.