[jQuery] BlockUI Dialog + FireFox - Breaks down

Hey,
When i'm trying to open BlockUI Dialog (Yes/No) few times in a row -
my FireFox (v2.0.0.8) breaks down.
Any solutions to this problem?
If i'm trying to open BlockUI few times without that dialog -
everything is ok...
The same problem is not only on my page, but on BlockUI demo page
also:
http://www.malsup.com/jquery/block/#dialog
Everything is ok with both IE 6/7.
Gediminas