Set with on treeview column

[apostolo <apostolo isr gmail com>]

Hi,

I have an application with a treeview with CellRendererCombo in each 
cell. This is working fine, with no known problem.
I can attach the model into the cell renderer, choose the desired item, etc.

The problem is in when I have a narrow cell, I can't see the items set 
in the combo renderer model.
For example if a cell in the treeview has the text "Is" or "And", when 
click the cell combo to select a new item,
I can't see anything in the Combo. This happens because the column of 
the treeview is too narrow (we made the cheat
and create a a larger cell, by introducing spaces, and the items appear).

I think the solution to this is to increase the length of the column. 
How can I perform this?

best regards
Filipe Apóstolo

P.S.: The program is a front-end to a fuzzy system. The items "Is" and 
"And" are normal in the combobox.