Why the <DIV> CSS applied for Repeater Control get Distorted when placed in UpdatePanel?

i am new to AJAX i am trying to update a Repeater Control When user Click on Search Button which is out side the updatePanel using Trigger event of UpdatePanel the CSS get Distorted when Repeater Control is Placed inside UpdatePanel Whhen the Update Panel is Removed Then the CSS is applied perfectly why does it happen?

Code:

 <div class="jqueryresultsBackground">
  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
  <ContentTemplate>
      <asp:Repeater ID="ResultsRepeater" runat="server">
                   <HeaderTemplate>
                       <table border="0" cellpadding="0" cellspacing="0" width="100%">
                           <tr>
                               <td>
                                   &nbsp;
                               </td>
                           </tr>
                       </table>
                   </HeaderTemplate>
                   <ItemTemplate>
                       <tr>
                           <td>
                               <table align="center" width="100%">
                                   <tr>
                                       <td align="left" class="searchResFieldName" width="40%">
                                           <asp:Image ID="Image1" runat="server" ImageUrl="~/images/deleted.png" 
                                               Style="z-index: 1; position: absolute; margin-left: -5px;" 
                                               Visible='<%# DeletedImageVisibility(Eval("IsActive"))%>' />
                                           <br />
                                           <%# Eval("UnicodeFullName")%>
                                       </td>
                                       <td width="10%">
                                          Col1
                                       </td>
                                   </tr>
                               </table>
                           </td>
                           <td width="10%">
                               Col2
                           </td>
                           <td width="10%">
                              Col3
                           </td>
                           <td width="8%">
                               Col4
                           </td>
                           <td width="5%">
                               Col5
                           </td>
                           <td width="10%">
                               Col6
                           </td>
                       </tr>
                       <tr>
                           <td align="left" class="searchResFieldName" width="35%">
                               <%# Eval("EnglishFullName")%>
                           </td>
                           <tr>
                               <td align="left">
                                   <%# Eval("HouseNumber")%>
                                   <br />
                                   <%# Eval("UnicodeAddress")%>
                               </td>
                               <td>
                                   <b><%# Eval("ConstituencyNumber")%></b>
                               </td>
                               <td>
                                   <b><%# Eval("PartNumber")%></b>
                               </td>
                               <td>
                                   <b><%# Eval("SerialInPart")%></b>
                               </td>
                               <td>
                                   <b><%# Eval("Age")%></b>
                               </td>
                               <td>
                                   <b><%# Eval("Sex")%></b>
                               </td>
                               <td>
                                   <b><%# Eval("CardNo")%></b>
                               </td>
                           </tr>
                           <tr>
                               <td>
                                   <%# Eval("Address")%>
                               </td>
                               <tr>
                                   <td>
                                   </td>
                                   <td align="left" class="searchResPrabhag" colspan="7">
                                       &nbsp;
                                   </td>
                               </tr>
                           </tr>
                           </table>
                           </td>
                       </tr>
                       <tr>
                           <td>
                               <hr />
                           </td>
                       </tr>
                   </ItemTemplate>
 
 
 <FooterTemplate>
                       <tr>
                           <td>
                               &nbsp;
                           </td>
                       </tr>
                       </table>
                   </FooterTemplate>
               </asp:Repeater>
 </ContentTemplate>
 
               <Triggers>
                   <asp:AsyncPostBackTrigger ControlID="SearchButton" EventName="Click" />
               </Triggers>
 
           </asp:UpdatePanel>
             <asp:HiddenField ID="CurrentPageHiddenField" runat="server" />
  </div>
 

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