Cute Editor uses JavaScript to access functionality that already exists in IE and Mozilla.

In IE this functionality is called "MSHTML"
 
http://msdn.microsoft.com/library/default.asp?url=/workshop/browser/editing/mshtmleditor.asp

In Mozilla this is called "Midas" 

http://www.mozilla.org/editor/midas-spec.html

If Opera add the required functionality to their browsers we will release an update to our product to support them (and we'd do this with pleasure as there is nothing we want more!).