Two components with the Same id can't be added to the application

Hi,

i have a problem with a slider control in one of my user controls. The user control has a modal popup extender with a slider control.
When i load the page for the first time, everything works great. After a second postback i get the error message shown bellow and the slider control is not turning into the visible textbox.


Message: Sys.InvalidOperationException: Two components with the same id 'TabContainer1_tabParts_Tab1Ctrl_sldQuantity' can't be added to the application.
Line: 4044
Char: 59
Code: 0
URI: http://localhost:59170/ScriptResource.axd?d=3Eg-fQsMWKYsGzpai2d16FzRZyxePoVWg0ZiVzxl0IzKq1Ft9y3T2wENj7O3x_hyqAvmWHH4ztSWl-WP85md5YtGYn_v721mKRQ3_QCPeFk1&t=ffffffffec2d9970



What could be the problem?

<%@ Control Language="C#" AutoEventWireup="true" CodeBehind="Parts.ascx.cs" Inherits="ADDTest.Parts1" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<link rel="Stylesheet" type="text/css" href="Styles/Stylesheet.css" id="style" runat="server" visible="false" />
                  
    <div style="height: 445px; vertical-align: top;" id="divParts">               
        <table width="100%">
            <tr valign="top">
                <td width="25%">
                    <div id="divSearch">
                    <p class="text">Search:</p>
                        <asp:TextBox ID="txtSearch" runat="server" Width="169px" 
                            ontextchanged="txtSearch_TextChanged"> 
                        </asp:TextBox>
                        <asp:DropDownList ID="ddlSearch" Width="91px" Height="22px" runat="server" AutoPostBack="True"
                        onselectedindexchanged="ddlSearch_SelectedIndexChanged" >
                            <asp:ListItem selected="True">Description</asp:ListItem>
                            <asp:ListItem>Manufacturer</asp:ListItem>
                            <asp:ListItem>Part ID</asp:ListItem>
                            <asp:ListItem>Bin Loc.</asp:ListItem>
                        </asp:DropDownList>
                        
                        <br />
                        <asp:Button ID="btnSearch" runat="server" Text="Search" 
                            onclick="btnSearch_Click" />
                        <asp:Button ID="btnClear" runat="server" Text="Clear" 
                            onclick="btnClear_Click" />
                        <br />
                        <br />
                        <asp:ListBox ID="lbxSearch" runat="server" Height="260px" Width="265px" 
                             SelectionMode="Multiple">
                        </asp:ListBox>
                        <br />
                        <asp:Button ID="btnShow" runat="server" Text="Show Images" 
                        onclick="btnShow_Click" /> 
                        </div>
                        <div id="divSearchBottom">
                            <asp:LinkButton ID="lbtnCheckout" runat="server" PostBackUrl="~/ViewCart.aspx"></asp:LinkButton>
                        </div>
                </td>
                <td width="75%" valign="top">
                
                    <div>
                    
                        <asp:DataList ID="DataList1" runat="server"  
                            RepeatColumns="3" RepeatDirection="Horizontal" BackColor="White" 
                            BorderColor="#E26020" BorderStyle="None" BorderWidth="1px" CellPadding="4" 
                            GridLines="Both"  >
                                <FooterStyle BackColor="#99CCCC" ForeColor="#E26020" />
                                <ItemTemplate>
                                <div class="Part">
                                <div class="PartImage">
                                    <table>
                                        <tr>
                                            <td>
                                                <asp:Image ID="imgPart" runat="server" Height="50" ImageUrl='<%#"ViewImage.ashx?part=" + Eval("Part") %>' 
                                                    GenerateEmptyAlternateText="true" Width="75" AlternateText="No Image" 
                                                    onmouseover="zoomToggle('100px','100px','200px','200px',this);" />
                                            </td>
                                            <td>
                                                <asp:Button ID="btnAdd" runat="server" Text="Add to Cart" Height="20px" 
                                                    CommandArgument='<%# Eval("Part") %>' CommandName="Action" onCommand="btnAdd_Command" />    
                                                <cc1:ModalPopupExtender ID="ModalPop" runat="server"
                                                    TargetControlID="btnAdd" PopupControlID="pnlAddPart" 
                                                    CancelControlID="btnPnlCancle" BackgroundCssClass="Modalbackground" 
                                                    DynamicContextKey='<%# Eval("Part") %>' DynamicServiceMethod="PopupMethod" DynamicControlID="txtHidden"  />
                                            <%--<asp:Button ID="btnDetails" runat="server" Text="Details" Height="20px" CommandArgument='<%# Eval("Part") %>' />  --%>
                                            </td>
                                        </tr>
                                    </table> </div>
                                <div class="PartDetails"></div>
                                    
                                    Part:
                                    <asp:TextBox ID="Parttext" runat="server" ReadOnly="True" TextMode="SingleLine" BorderStyle="None" BorderWidth="0" CssClass="textbox" Text='<%# Eval("Part") %>'></asp:TextBox> 
                                    <br />
                                    Desc.: 
                                    <asp:TextBox ID="Desc1Text" runat="server" Rows="2" ReadOnly="True" TextMode="MultiLine" BorderStyle="None" BorderWidth="0" CssClass="textbox" Text='<%# Eval("Desc1") %>'></asp:TextBox>
                                    <br />
                                    Inv: <asp:TextBox ID="InvText" runat="server" ReadOnly="True" TextMode="SingleLine" BorderStyle="None" BorderWidth="0" CssClass="textbox" Text='<%# Eval("Inv") %>' Width="147px"></asp:TextBox>
                                    <br />
                                    BinLoc:<asp:TextBox ID="BinLocText" runat="server" ReadOnly="True" TextMode="SingleLine" BorderStyle="None" BorderWidth="0" CssClass="textbox" Text='<%# Eval("BinLoc") %>' Width="126px"></asp:TextBox>
                                    <br />
                                    Manufacturer: <asp:TextBox ID="ManufacturerText" runat="server" ReadOnly="True" TextMode="SingleLine" BorderStyle="None" BorderWidth="0" CssClass="textbox" Text='<%# Eval("Manufacturer") %>' Width="85px"></asp:TextBox>
                                    <br />
                                </div>
                                </ItemTemplate>
                                <ItemStyle BackColor="White" ForeColor="#E26020" />
                                <SelectedItemStyle BackColor="#009999" Font-Bold="True" ForeColor="#CCFF99" />
                                <HeaderStyle BackColor="#003399" Font-Bold="True" ForeColor="#CCCCFF" />
                        </asp:DataList>
                        </div>
                        
                        <div id="Navigation" class="navigation" runat="server">

                            <div id="leftnav">
                                <asp:Button ID="btnPreviousPage" runat="server" Text="Previous Parts" OnClick="btnPreviousPage_Click" />
                                &nbsp;
                            </div>
                            
                            <div id="rightnav">
                                &nbsp;
                                <asp:Button ID="btnNextPage" runat="server" Text="More Parts"  OnClick="btnNextPage_Click" />
                            </div>
                        
                            <div id="numnav">
                                <asp:Label ID="PagerLocation" runat="server" />
                            </div>
                        
                        </div>
                </td>
            </tr>
        </table>
 </div> 
 
<asp:Panel ID="pnlAddPart" runat="server" style="display:none">

    <asp:ObjectDataSource ID="odsChrgDep" runat="server" 
        OldValuesParameterFormatString="original_{0}" SelectMethod="GetData" 
        TypeName="ADDTest.Datasets.dsCribstoreTableAdapters.ChrgDepTableAdapter"></asp:ObjectDataSource>
  <asp:UpdatePanel ID="upAddPart" runat="server" UpdateMode="Always">
    <ContentTemplate>
        <h1>Select Quantity:</h1>
        <asp:TextBox ID="txtHiddenSlider" runat="server"></asp:TextBox>
        <asp:TextBox ID="txtVisibleSlider" runat="server"></asp:TextBox>
        <cc1:SliderExtender ID="sldQuantity" runat="server" 
            TargetControlID="txtHiddenSlider" BoundControlID="txtVisibleSlider" 
            Maximum="50" Minimum="1" />      
        <asp:RangeValidator ID="RangeValidator1" runat="server" 
            ErrorMessage="RangeValidator" ControlToValidate="txtVisibleSlider" 
            MaximumValue="10" MinimumValue="1" Font-Bold="True" Font-Italic="True" 
            Font-Size="Large" Type="Integer" >Not enough Parts in Stock</asp:RangeValidator>
        <br />
        <h1>Select Charge Department:</h1>
        <asp:DropDownList ID="ddlPnl" runat="server" DataSourceID="odsChrgDep" 
            DataTextField="ChrgDepDesc" DataValueField="ChrgDep" />  
            <br />
        <asp:Button ID="btnPnlOk" runat="server" Text="OK" onClick="btnPnlOk_Click" /> 
        <asp:Button ID="btnPnlCancle" runat="server" Text="Cancle" />
        <asp:TextBox ID="txtHidden" runat="server" style="display:none" />
  </ContentTemplate>
 </asp:UpdatePanel>
</asp:Panel>

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