The issue is a flickering/multiply of a Cute editor toolbar (combo box elements only). The issue is manifested only in Firefox. On a very few comps I have experienced this. First I thought that this is happening only in our application but than I realize the same issue on your demo site.

 

First spotted  on new Windows 7 comp, but now on this one:

 

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.2) Gecko/20100316 Firefox/3.6.2

 

Any ideas or experiences about it???