[jQuery] slider ui 1.6 with different handle class doesn't work

I was using jQuery UI 1.5.3 and after I upgraded to 1.6 some of my
sliders are not working properly. To be more specific, once I let go
of the slider handle after moving it, it still moves with the mouse,
even though my mouse button is not pressed anymore.

It seems that if I used a different handle than the default, the
above
issue occurs. So

$('#someId').slider(); works fine, but $('#someId').slider({ handle:
'.someHandleClass' }); doesn't.

Any ideas?