Treeview column width changed signal

[Jeffrey Barish <jeff_barish earthlink net>]

Is there a way to be notified when the width of a column in a treeview
changes?  I would like to record the new column widths so that I can set
them to the same values the next time the window opens.  The only signal in
TreeViewColumn is clicked, which doesn't seem to do what I need.
-- 
Jeffrey Barish