drop effect bug ?

Under Safari 3 ( Mac & win ) and IE 7 :
The Drop effect applied on a div positioned at the right of the window
with position: absolute et and right : 10 does its thing, but also
moves the div at the left of the screen before applying the effect
(works as expected on FF2 & 3, Mac & Win)
example here : http://www.logedesgardes.com/
try to close the white and black ad in the top right