Button Event is not firing inside Ajax Tab container

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C#

ASP.NET

Ajax

Hi..,

I am currently working for the first time in ajax Tab container,i have 2 tabs, In first tab, i'm just getting user input and save it into Sql,and in second tab, displying some data in grid. My problem is in my first tab, when i click save button, it doesnt fires button_click event.where else all the other events like Gridview1_PageIndexChanging and DropDown1_SelectedIndexChanged works good.. any help??

my code:

<asp:ScriptManager ID="ScriptManager1"  runat="server" ></asp:ScriptManager>
<asp:TabContainer ID="TabContainer1"  CssClass="fancy fancy-green"   runat="server"  Height="357px" Width="950px" ActiveTabIndex="0" >
    <asp:TabPanel ID="Tab0" HeaderText="Add Inventory"  runat="server">
    <ContentTemplate>
    <div id="Add1" class="divinventory5" runat="server">
    <h1 align="center" >Add Inventory</h1>
<table cellpadding="10">
<tr>
<td><asp:Label ID="Label2" Text="Name Of Inventory:" runat="server"></asp:Label></td>
<td> <asp:TextBox ID="Inventory" CausesValidation="false"  CssClass="myInput" runat="server"/></td>
</tr>
<tr>
<td><asp:Label ID="Label3" Text="Identity(eg:Serial Number):" runat="server"></asp:Label></td>
<td> <asp:TextBox ID="txtidentity" CausesValidation="false" CssClass="myInput" runat="server"/></td>
</tr>
<tr>
<td>
<asp:Button ID="Button1" CausesValidation="false" Text="Add"  Width="150px"
          CssClass="loginareabuttons" runat="server" onclick="Button1_Click"  />
</td>
<td>
<asp:Button ID="Button2" CausesValidation="false"  Text="Cancel" Width="150px"
          CssClass="loginareabuttons" runat="server" onclick="Button2_Click"  />
</td>
</tr>
</table>
</div>
    </ContentTemplate>
    </asp:TabPanel>
    <asp:TabPanel ID="Tab1" HeaderText="Total Render Inventory"  runat="server">
     <ContentTemplate>
    <div id="Div1" class="grd1" runat="server">
<asp:GridView ID="Gridview1" AllowPaging="true"  rowstyle-cssclass="rowHover"  PageSize="6"
        captionalign="Top"   AutoGenerateColumns="false"
        runat="server"  Width="950px" Height="370px"  DataKeyNames="I_id"
         HeaderStyle-BackColor="black" HeaderStyle-ForeColor="White"
        PagerSettings-Position="Bottom" PagerStyle-BackColor="Black"
        PagerStyle-ForeColor="White" onpageindexchanging="Gridview1_PageIndexChanging">
<Columns>
<asp:BoundField DataField="RenderName" ItemStyle-HorizontalAlign="Center" HeaderText="Name" ItemStyle-Width="100px" />
<asp:BoundField DataField="RenderInventory" ItemStyle-HorizontalAlign="Center" HeaderText="Render-Inventory" ItemStyle-Width="100px" />
<asp:BoundField DataField="Rendermodel" ItemStyle-HorizontalAlign="Center" HeaderText="Render-Model" ItemStyle-Width="100px"     />
<asp:BoundField DataField="RenderDate" ItemStyle-HorizontalAlign="Center" HeaderText="Date of Render"  ItemStyle-Width="100px" />
</Columns>
</asp:GridView></div>
    </ContentTemplate>
    </asp:TabPanel>