treeview with fixed in place first row

[DEXTER <mydexterid gmail com>]

Hi there,

I have a treeview and what I'd like to achieve is that the first row
of the treeview (under the column headers) be fixed at its place so
the scrolling won't affect it. I would use this very first row to
filter the treeview. Attached an image showing the what I would like
to make. (As you can see there's a row under the column headers
including comboboxes)

I was able to access the column headers' buttons. (TreeViewColumn) The
TreeViewColumn has a function called set_widget, and I can set any
widget _inside_ that button, but it is not good for me, because if I
set a combobox with this, than - since it is inside the button - it
acts like a button too.

I also tried to replace that button with a vbox (and put the button
and a combobox in the vbox) but as soon as I removed the button from
the treeview, it complaind about propagating expose cannot be done (
g_assert (child->parent == GTK_WIDGET (container));) I think this is
because this button is a private child of the treeview, so it won't
let me replace it with any other widget.


Is there any other way to achieve this? Any suggestions are welcome.

Thx.
Balazs