Still haven't been able to solve this. This is the configuration we're using:
<ce:Editor id="txtDescription" runat="server" Width="600px" URLType="Absolute" EnableContextMenu="True" AutoConfigure="Simple" UseRelativeLinks="False" ThemeType="OfficeXP" ShowBottomBar="true" ShowTagSelector="False" Height="400px" ShowGroupMenuImage="False" RemoveServerNamesFromUrl="False" EditorWysiwygModeCss="/Styles/default.css" AutoParseClasses="false">
<FrameStyle Height="100%" BorderWidth="1px" BorderStyle="Solid" BorderColor="Silver" Width="100%"
CssClass="CuteEditorFrame" BackColor="White" ></framestyle>
</ce:Editor>
Is there something else we should do?