Gtk3 and resizing GtkTreeView columns

[Michael Cronenworth <mike cchtml com>]

I ported an app from GTK2 to GTK3. Aside from lots of function renaming 
and layout adjusting due to the flipping of the expand flag...

I have a problem with columns in GtkTreeView widgets. In GTK2, resizing 
a column with the mouse past the width of the visible tree wouldn't 
cause the whole window to resize. In GTK3 it does, and when the window 
is resized you cannot shrink the window until you shrink the TreeView.

How do you get tree views in GTK3 to act like GTK2?

Thanks,
Michael