Liststore and editing cancelled event

[Mike Martin <redtux1 gmail com>]

Is there any way to disable the editing-cancelled event on cellrenderertext.

Background

When I have a liststore contained within a treestore I want the value to be
be saved if I click on a button not contained within the treeview, so that
it does not just dissapear
Focus events dont seem to work as the treeview still has focus

thanks

Mike