I have the same issue with Firefox 3.0.2 and CuteEditor 6.2. I cannot data enter and when I click on the bold button, for instance, I get:  Command 'Bold' Error : Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMNSHTMLDocument.execCommand].

I understand the suggested workaround in the div styling rather than setting visible to true/false as in below:

 

 

but making this change will not be so simple in my application.  My cuteEditor elements are embedded in usercontrols within a framework and are hidden at the level of a parent of a parent of a parent element

 

I have no issue in any other browser.  Are there any other suggested workarounds?