In addition, I just Open JavaScript Console of the FireFox and guess:

Error: FournierTransformationDeleteMethod is not defined
Source File: http://www.levelextreme.com/Javascript/List.js
Line: 91

>Hi Borislav
>
>>I have the same problem with Hiding Dashboard, Delete messages. But I think its because I use Mozilla Firefox. In IE everithing is fine.
>
>Same here I have FireFox, but then it was working these a days till couple of days back, also there seems to be a change in the UT server or whatever it is called, now as you will notice we have LevelExtreme in the address box.
>
>Some change seems to have triggered this.