Problem dragging treeview column headings

[skip pobox com]

We use Gtk & PyGtk 2.6 at work.  When dragging treeview column headings
around I frequently lose control of the heading and it winds up "stuck"
lower than the other headings.  Something like this in bad ascii art:

    +------+------+      +------+
    | col1 | col2 |      | col4 |
    +------+------+------+------+
                  | col3 |
                  +------+

I don't believe it's a PyGtk problem.  One of my colleagues says he's seen
it in C-based Gtk programs as well.    I get these sorts of error messages
in my shell window:

    GtkWarning: _gtk_tree_view_column_start_drag: assertion
    `tree_view->priv->column_drag_info == NULL' failed

I have two questions.  One, is this a known problem (it happens here so
frequently I'd have to believe it is)?  Two, has it been fixed in later
versions of Gtk?

I apologize for posting this kind of question to the pygtk and gtk mailing
lists, since I should (in theory) be able to find the answer in Bugzilla.  I
tried briefly, but just like every other time I've challenged the beast to
combat, my attempts to slay it failed, and I slinked home without reaching
my quest, humiliated by a mere HTML form once again...

Thx,

-- 
Skip Montanaro - skip pobox com - http://www.mojam.com/
"On the academic side, effort is too often expended on finding precise
answers to the wrong questions." Baxter & Rennie, in "Financial Calculus"