GridPanel Checkbox Selection gets lost with Linq Data Source after select

[BLOZZY]

hi,

I got a GridPanel with a LinqDataSource as a Store. After I select the Row with the Checkbox, the row gets unselected after 1 second ? please help.

<asp:LinqDataSource ID="LinqDataSource1" runat="server" EnableViewState="true"
ContextTypeName="ImmoBench.ImmoBenchDataContext" EnableDelete="True" 
EnableInsert="True" EnableUpdate="True" TableName="REF_objects" 
OrderBy="Projektabschluss desc, Projektname">
</asp:LinqDataSource> 
 
<ext:Store ID="Store2" runat="server" 
DataSourceID="LinqDataSource1"
AutoLoad="true"....
 
<ext:GridPanel 
runat="server" 
ID="GridPanel2" 
StoreID="Store2" 
Title="Referenzobjekte" 
Height="350"
Collapsible="true"
AutoWidth="true"
StripeRows="true"
AutoRender="true" >
........
<SelectionModel> 
<ext:CheckboxSelectionModel ID="CheckboxSelectionModel1" ColumnPosition="0" EnableViewState="true" SingleSelect="false" runat="server" >
<DirectEvents>
<SelectionChange OnEvent="AddChecked" ViewStateMode="Enabled" AutoDataBind="false"> 
<ExtraParams>
<ext:Parameter Name="Values" Value="Ext.encode(#{GridPanel2}.getRowsValues({selectedOnly:true}))" Mode="Raw" />
<ext:Parameter Name="direct" Value="true" Mode="Value"></ext:Parameter>
</ExtraParams> 
</SelectionChange>
</DirectEvents> 
<Listeners> 
<RowSelect Handler="record.set('Active', 'true');" />
<RowDeselect Handler="record.set('Active', 'false');" />
</Listeners>
</ext:CheckboxSelectionModel> 
</SelectionModel> 
 
 
The Function AddChecked is EMPTY !!!

thx