Scrollbar flickers when clock run

[Flávio Alberto Lopes Soares <flavio maqplas com br>]

 Hello all, I'm using GTK 1.2 and my application has a clock that run
always when I start the program, I make this clock using gtk_timeout_add
with 1 second of interval and each 1 second it changes a gtk_label to
show the elapsed time, and the program has too a CList with vertical
scrollbar, but this scrollbar is making randon flickering when the
numbers (gtk_label) of clock are swapped, why this occurs ? How to fix
this ?

Thanks in advance for all help

Flavio Alberto