There is one combobox column in a gridpanel,
I want it show the display field value in column and also the tooltips also show the display field, please help, thanks.

<%@ Page Language="C#" %>
 
<%@ Register Assembly="Ext.Net" Namespace="Ext.Net" TagPrefix="ext" %>
 
<script runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!X.IsAjaxRequest)
        {
            TypeGridStore.DataSource = new object[] 
            { 
                new object[] { "1", "long text 1" },
                new object[] { "2", "long text 2" },
                new object[] { "3", "long text 3" },
            };
            TypeGridStore.DataBind();
            
            GridStore.DataSource = new object[]
            {
                new object[] { "2" },
            };
            GridStore.DataBind();
        }
    }
</script>
 
<!DOCTYPE html>

<html>
<head runat="server">
    <title>Ext.NET v2 Example</title>
    <script>
        var TypeGridRenderer = function (value) {
            var r = App.TypeGridStore.getById(value);
            if (Ext.isEmpty(r)) {
                return "";
            }
            return r.data.Value;
        };
    var onBeforeShow = function (toolTip, grid) {             
        var view = grid.getView(),
            store = grid.getStore(),
            record = view.getRecord(view.findItemByChild(toolTip.triggerElement)),
            column = view.getHeaderByCell(toolTip.triggerElement),
            data = record.get(column.dataIndex);
        

        var td = toolTip.triggerElement,
            cell = Ext.fly(td).child("div").dom;

        toolTip.update(data);
        return true;
    };
    </script>
</head>
<body>
    <ext:ResourceManager runat="server" />
                        <ext:GridPanel
                            runat="server"
                            ID="ShowGrid"
                            ColumnWidth="1"
                            EnableColumnHide="false" >
                            <Store>
                                <ext:Store 
                                    ID="GridStore" 
                                    runat="server" >
                                    <Model>
                                        <ext:Model runat="server" Name="ProInfoModel" >
                                            <Fields>
                                                <ext:ModelField Name="Type" Type="String" />
                                            </Fields>
                                        </ext:Model>
                                    </Model>
                                </ext:Store>
                            </Store>
                            <ColumnModel>
                                <Columns>
                                    <ext:Column runat="server" Text="ProType" DataIndex="Type" Width="80" >
                                         <Editor>
                                            <ext:ComboBox 
                                                ID="TypeGridCombo" 
                                                runat="server" 
                                                QueryMode="Local" 
                                                DisplayField="Value"
                                                ValueField="Key"
                                                EnableKeyEvents="true">
                                                <Store>
                                                    <ext:Store ID="TypeGridStore" runat="server">
                                                        <Model>
                                                            <ext:Model runat="server">
                                                                <Fields>
                                                                    <ext:ModelField Name="Key" />
                                                                    <ext:ModelField Name="Value" />
                                                                </Fields>
                                                            </ext:Model>
                                                        </Model>
                                                    </ext:Store>
                                                </Store>
                                            </ext:ComboBox>
                                         </Editor>
                                    </ext:Column>
                                </Columns>
                            </ColumnModel>
                            <View>
                                <ext:GridView runat="server" TrackOver="true" EnableTextSelection="True" >
                                </ext:GridView>
                            </View>
                        </ext:GridPanel>
    <ext:ToolTip
        runat="server"
        Target="={#{ShowGrid}.getView().el}"
        Delegate=".x-grid-cell"
        TrackMouse="true">
        <Listeners>
            <BeforeShow Handler="return onBeforeShow(this, #{ShowGrid});" />
        </Listeners>
    </ext:ToolTip>
</body>
</html>