After upgrading from Firefox 3.6 to FF4 i was surprised to see that jQuery UI Sortable has stopped working (I am using jQuery (1.4.2) with jQuery UI (1.8.5)) and i get this error (from firebug)
this.helper is null
dev/js/jquery-ui-1.8.5.custom.min.js Line 264
I've had a look around but not found any reason for this error. I even upgraded jQuery UI to the latest version (1.8.11) but that did not help.
If anyone has any insight why this is happening (or a fix) i would greatly appreciate your input!
Thanks.
Hello mtlgray: I've just tested jQueryUI Sortable demo with my Firefox 4.0 and it works OK.
Maybe your problem is caused by some misconfiguration in your project. Please give a try to FireQuery (for Firebug), perhaps it helps you to find out the cause.
来源：https://stackoverflow.com/questions/5543862/firefox-4-issue-with-jquery-ui-sortable