Canvas scrolling - scrollBar become "disabled" on change in canvas

[Askari]

Hi,
   I do a "perso"widget where have two scrolls (one vertical, one 
horizontal) for a canvas.
When, the first time, I added widget in the canvas, the scroll self-ajust 
and when I move scrollbar, the surface's canvas "moved". But when I deleted  
(.destroy) this first widgets and that a added other widget, the scrollBar 
become disabled (ajust for no scroll on the canvas). What/where is the 
problem?


I use basic widget (scrollBar, Canvas, Frame, etc.) from library's Tkinter 
(and python 2.3.4 on WinXp Pro (sp1))

Askari