bugs in overlap of magnifier

There is a bug if i turn the overlap to true in firefox (linux). The effect is too far from the pic even if i turn distance to 0.

And the cpu usage is too high.

My code is like this:

<script>

$('#abc').magnifier({ overlap: true, zIndex: 10});

</script>

<div id="abc"><img src"/"><img src"/"><img src"/"></div>