First of all - great plugin!
I set up a site for a client and it was just reported to me that he cannot order posts in Firefox (WordPress Version 3.7.1 and Firefox 26). Basically, drag and drop just dont work. Apparently it is working fine in Safari for him and also I myself have also not experienced any problems in Chrome, Safari and Firefox.
Any idea what the issue could be or how I could ask him to debug?
Thanks so much for any help!