There's a aspx with only one ISWebDesktop which has 3 WebTabItems,every WebTabItem has a WebGrid. The web page throws the error：

can not find mehod:“Boolean ISNet.WebUI.ISNetControl.IsInternetExplorer11Browser()”

•.šž.‚ž() +0
   •.šž.ž() +647
   •.šž.RenderControlContents() +32
   ISNet.WebUI.RenderDHTML.RenderControl() +123
   ISNet.WebUI.RenderDHTML.GetHTMLString() +248
   ISNet.WebUI.ControlRenderer.RenderDHTMLControlToStream(HtmlTextWriter output) +29
   ISNet.WebUI.ControlRenderer.Render(HtmlTextWriter output) +816
   ISNet.WebUI.ISNetControl.RenderContents(HtmlTextWriter writer) +1093
   System.Web.UI.WebControls.WebControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19
   System.Web.UI.HtmlControls.HtmlForm.RenderChildren(HtmlTextWriter writer) +163
   System.Web.UI.HtmlControls.HtmlContainerControl.Render(HtmlTextWriter writer) +32
   System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTextWriter output) +51
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
   System.Web.UI.HtmlControls.HtmlForm.RenderControl(HtmlTextWriter writer) +40
   System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children) +134
   System.Web.UI.Control.RenderChildren(HtmlTextWriter writer) +19
   System.Web.UI.Page.Render(HtmlTextWriter writer) +29
   System.Web.UI.Control.RenderControlInternal(HtmlTextWriter writer, ControlAdapter adapter) +27
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer, ControlAdapter adapter) +99
   System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +25
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1266

WebDesktop version:4.0.7200

WebGrid version:8.0.7200

Browser:ie10 version 10.0.9200.16736  updateVersion:10.0.11

<ISWebDesktop:WebTab ID="wtComm" runat="server" Height="100%" Width="100%" ImagesDirectory="../CommonLibrary/Images/WebDesktop/"
            ScriptDirectory="../CommonLibrary/WebDesktop/V4_0_7200/" SharedScriptDirectory="../CommonLibrary/Shared/"
            RenderMode="RoundCorner" ActiveTabIndex="0" ContentMode="UseIFrame" ContainerDropShadow="True">
            <TabItemStyle>
                <Active BorderStyle="Solid" BackColor2="WhiteSmoke" BorderWidth="1px" BorderColor="#9EB6CE"
                    BaseStyle="Normal" BackColor="White" GradientType="Vertical">
                </Active>
                <Over BaseStyle="Normal" BackColor="WhiteSmoke">
                </Over>
                <Normal BorderStyle="Solid" BorderWidth="1px" BorderColor="Gray" Width="100%" Font-Size="9pt"
                    Font-Names="Tahoma" BackColor="Gainsboro" Height="100%" Cursor="Hand">
                    <Padding Top="2px" Left="10px" Bottom="0px" Right="10px"></Padding>
                </Normal>
            </TabItemStyle>
            <DisabledStyle ForeColor="Gray">
            </DisabledStyle>
            <TabPages>
                <ISWebDesktop:WebTabItem ContentMode="UseIFrame" ContentURL="a.aspx"
                    Name="tab_travel_item" Text="A">
                </ISWebDesktop:WebTabItem>
                <ISWebDesktop:WebTabItem ContentMode="UseIFrame" ContentURL="b.aspx"
                    Name="tab_travel_assistance_item" Text="B">
                </ISWebDesktop:WebTabItem>
                 <ISWebDesktop:WebTabItem ContentMode="UseIFrame" ContentURL="c.aspx"
                    Name="tab_project_category_item" Text="C">
                </ISWebDesktop:WebTabItem>
            </TabPages>
            <FrameStyle Overflow="Hidden" OverflowX="Hidden" OverflowY="Hidden">
                <Padding Bottom="16px" />
            </FrameStyle>
            <RoundCornerSettings FillerBorderColor="255, 199, 60" TopBorderColor="230, 139, 44">
            </RoundCornerSettings>
            <ContainerStyle BorderStyle="Solid" BorderWidth="1px" BorderColor="#9EB6CE" Width="100%"
                BackColor="WhiteSmoke" Height="100%" Overflow="Auto" OverflowX="Auto" OverflowY="Auto">
                <Padding Top="5px" Left="5px" Bottom="5px" Right="5px"></Padding>
            </ContainerStyle>
        </ISWebDesktop:WebTab>