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?