Strange XMMS window snapping

[Pixelbrei]

XMMS shows a quite strange behaviour:
I set XMMS to save window positions on exit...
and it almost works.
but everytime i launch XMMS, theres a distance between the main window and the equalizer of about 2 pixels. I always move the main window to snap to the equalizer again, but this is gone after i exit XMMS.

Does anyone know how to fix that?

btw: my window manager is WindowMaker (if thats important)