Dynamic update using Wxagg back-end

Hi all,
I’m trying to make my own matplotlib back-end using FigureFrameWx, FigureManagerWx, FigureCanvasWx.
My problem is that when i use the NavigationToolbar2Wx for scrolling the axes values, my graph is updates but the values of the axes are not. The consequence are visible on this picture : http://dl.free.fr/RHWELK1d/bug.png . The only way that I have found for refreshing all the figure is to resize the window…

I have tried to correct the bug but without success. I know that the scrolling of the toolbar uses the dynamic_update method that call the canvas.draw method. I have seen a note at the beginning of the backend_wx.py file :

Fixed this release:

Bug #866969: Dynamic update does not function with backend_wx [JOD]

I don’t now if there is any link with my problem… So do you have an idea of the problem ?

I am using matplotlib 0.90.1 with python 2.4.

Thank you for your answers