problem with expose event

[Reymond Dominique <reymond d labogeo pf>]

Hello 

could somebody tell me why a gtk_area is redrawn several times after an "expose event" :until 5 to 6 times, 
specially when we maximize it.

I have tested the event count in the callback function.
../..
if (evt->count > 0) return;  
../..

but it does not avoid this problem:
the evt->count is quasi always equal to 0.

I don't know what to do more...
(it is a big waste of time when redrawing several millions of points)

thank you for your help

Dominique Reymond