drawing area & multithreading

[Giaslas Georgios <giaslas ceid upatras gr>]

hi,
i have the following problem.
if i have a non-multithreaded program with a drawing area and i call
gtk_widget_draw, it calls the expose event fuction which calls
gdk_draw_rectangle and
then the drawing area updates normally.
the problem is that if i create another thread and call gtk_widget_draw
from that thread the expose event function is called, but the drawing
area isn't updated until i focus/unfocus the window or some widget in the
window.

can you help me with that?
i use LINUX, gtk+ 1.2.7, POSIX threads, XFree86 4.0.0

thanx