Bug with Opera and draggables

Bug with Opera and draggables


Test page: http://www.simpsoncrazy.com/content/games/jigsaw.html
Using jQuery 1.2.6 and UI 1.5.3
I have a couple of problems with this in Opera 9.6 - firstly when I
drag something for the first time it jumps to the bottom of the screen
(or goes off screen altogether). It seems that if I scroll down
further, the further away the element jumps to.
Second problem is if I add a margin to the elements, in Opera they
don't snap to a perfect line any more. On one side the pieces overlap,
and the other there is a gap between them.
My jQ code is simply:
$(function() {
$(".jigsawPiece").draggable( { snap: true, snapMode: 'outer' } );
});
It is applied to all the jigsaw pieces so they should all snap to each
other. It's working fine in Firefox. The demos on the jQ site work
fine for me too, so maybe there's something I've done wrong in my code?