I seem to have the opposite problem. Only affects my tinymce textarea in IE. All other form elements and browsers do not show the following behavior I'll describe...
My webapp basically like an address book. click a name, and then an ajax call loads some HTML about the person, called a "business card." I can click "edit" in that business card, and an HTML form is loaded via ajax call with the business card data pre-loaded in the HTML form's fields. one of these elements is a textarea, with tinymce plugin on it. I can edit the content and submit no problem... THE FIRST TIME. after the submission, the business card is reloaded via ajax, and the new content displays fine. By SUBSEQUENTLY EDITTING AGAIN, I can no longer change the TEXTAREA/ TINYMCE content, but all other text inputs, checkboxes, etc., continue to change just as expected. Any idea why the textarea w/ tinymce only works once in this ajax environment? Firefox works fine. All other form elements work fine. Even textarea WITHOUT tinymce works fine. All of the time. :)