C# - Prevent GridView Saving Data From Build To Build In Visual Studio?

I have a question regarding a situation that occurs with GridView, ObjectDataSource in ASP .NET application. The GridView is linked to the ObjectDataSource and both are included within an UpdatePanel letting the GridView to fill in an asynchronous way from a form in the same page so it gets more rows as the user enters the data:

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
DataSourceID="ObjectDataSource1">
<Columns>
<asp:BoundField DataField="Name" HeaderText="Name" ReadOnly="True"
SortExpression="Name" />
<asp:BoundField DataField="Periodicty" HeaderText="Periodicty" ReadOnly="True"
SortExpression="Periodicty" />
</Columns>
</asp:GridView>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
SelectMethod="GetSessionNames" TypeName="Simulation"></asp:ObjectDataSource>
<asp:Label ID="Label27" runat="server" Text="Label"></asp:Label>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="NewWebSessionButton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>

I start the project with Visual Studio 2008, fill the form and it works correctly. Then I stop the execution: rerun again and the data I entered in the previous run is in the GridView. Is like some sort of cache saved the data from the session before. I checked that EnableCaching property is set to false for the ObjectDataSource. If I Rebuild Web Site in Visual Studio (not just Build) then it works corretly leaving the GridView empty. Is this caused just becuase of Visual Studio? Can it be turned off? And will it happen in the final IIS it will run on?