Hi
I find another problem using tabPanel,but it is simple. The problem (I think) is because the render dosen't close de "br" tag, Im resolved this problem overriding the method writeTopTabSpacer of TabPanelRenderer:
private void writeTopTabSpacer(ResponseWriter w, UIComponent comp, String style, String classStyle) throws IOException {
w.startElement("td", comp);
w.writeAttribute(STYLE, style, null);
w.writeAttribute(CLASS, classStyle, null);
w.startElement("br", comp);
/*^closing tags */
w.endElement("br");
/*^closing tags */
w.endElement("td");
}