I'm using a DwtHtmlEditor in HTML mode inside a DwtTabViewPage. When this tab is the only one in the DwtTabView, I have no problem. But if another tab is the default, when I switch to the editor's tab and click inside the widget, I get this exception (in FireFox, not in IE):

Exception ``[Exception... "Component returned failure code: 0x80004005 (NS_ERROR_FAILURE) [nsIDOMNSHTMLDocument.queryCommandState]" nsresult: "0x80004005 (NS_ERROR_FAILURE)" location: "JS frame :: http://.../zimbra/boot.js :: anonymous :: line 15392" data: no]'' thrown from function anonymous()

line 15392 of our boot.js corresponds with line 620 of DwtHtmlEditor.js:

Code:
var iFrameDoc = this._getIframeDoc();
ev.isBold = iFrameDoc.queryCommandState(DwtHtmlEditor.BOLD_STYLE); // line 620
ev.isItalic = iFrameDoc.queryCommandState(DwtHtmlEditor.ITALIC_STYLE);
Any ideas about what's going wrong?
--Chouser