David,

thanks for sharing this: unfortunately this is not working for me, if I place such a control in my skin directory the popup for html editor opens but then fails to load the editor  - it shows the loading image, but then remains blank.

I only tried changing the control language to vb instead of c#, since my other skin files use vb, but the result is the same. Am I missing something else?

Thank you,

al.

Ben, 
thanks for the suggestion.  This is not working for me: I tried emptying cache both on client and server, restarting application and using a couple of different browsers but no way, if I enable popups I never see my classes loaded into the editor.

I now switched popups off, which is not so a big problem but... I'd like to understand. Could it be the my editor.css makes loading fail? I don't see any error, nor clientside nor server side.