X noisy and dirty sessions on Compaq Armada

[Eduardo Díaz Uriarte <ediazuri@wanadoo.es>]

Hi,

I've got a Compaq Armada 1510 running Xfree86 4.x. I finally configured
my x server so now I can play window maker.

But, I have a problem. Whenever I move the mouse cursor by the top of
the display, everywhere appear slices of the icons and windows that are
at the top.

By the way, I always can see a bit of the grey pattern of the x windows
(the one you see when they are starting) at the top of the display (the
rest shows what it should as I configured wm).

I don't know what it must be.

Any hints.

Thank you very much