I am still having this issue, and have not found a work around. In fact, the postback problem has grown in scope. If I change the style sheet based on a custom drop down list using this code based on the style sheet chosen by the user, any subsequent postbacks are lost.
Editor1.EditorWysiwygModeCss =
"~/Default.css"
Is there anyway at all to resolve this issue? I've been waiting for well over a month for a response. Thank you.