Similar if not the same problem here.

I am trying to set the initial text of the editor to something from the database. The editor resides in a 'hidden' block until the user clicks on something to 'unhide' it.   I'll include the example at the bottom.

Works fine in IE, but throws an error in FF. The error *only* is thrown if the encompassing block is hidden. Take the 'display:none' out and we're good as gold.

----Begin Head----
myEditor.Text = [[FromDataBase]]
----End Head----

----Begin Body----
<a href="#" onClick="jsChangeStyleToBlock('DivEdit'); return false;">Show Editor</a>
<div id="DivEdit" style="display:none;">
  <CE:Editor id="myEditor" runat="server"></CE:Editor>
</div>
----End Body----

----Begin Error (Thx to FireBug)----
uncaught exception: [Exception... "Component returned failure code: 0x80040111 (NS_ERROR_NOT_AVAILABLE) [nsIDOMNSHTMLDocument.designMode]" nsresult: "0x80040111 (NS_ERROR_NOT_AVAILABLE)" location: "JS frame :: http://SITE/CuteEditor/Load.ashx?type=scripts&file=Gecko_Loader :: Ox87a :: line 3" data: no]
----End Error----

Edit: Oh, btw, this worked fine before I upgraded us to the most recent version.