BlockUI jquery plugin keeps page blocked after "back" button. Opera/FireFox

I use jquery blockUI plugin (v2) and call $.blockUI when user submits a form. Web page smoothly fades out and new page appears. That's ok. But when user presses "back开发者_StackOverflow社区" button in opera/fire fox he observes fade out page with hourglass mouse cursor that is completely blocked.

Chrome/IE visualize page ok.

What would you suggest?

Thank you in advance!

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Finally I found workaround.

$(window).unload(function() {
                $.unblockUI();                
})