problem with timer and watermark

hi,

i have used an timer and adrotor inside update panel control in my master page of asp.net web site. in another page i have some text boxes with watermark.

my problem is that the watermarks refresh when timer tick raises.

my code for pages.aspx:

<%@ Page Language="C#"  MasterPageFile="~/MasterPageMain.master"  AutoEventWireup="true" maintainscrollpositiononpostback="true"  CodeFile="Pages.aspx.cs" Inherits="Pages" %><asp:Content ID="Content1" runat="Server" ContentPlaceHolderID="ContentPlaceHolderMain"><asp:ScriptManagerProxy id="ScriptManagerProxy1" runat="server"></asp:ScriptManagerProxy><div class="grid" dir="rtl"><div class="rounded"><div class="top-outer"><div class="top-inner"><div class="top"><h2 style="color:Yellow">
                                your comment</h2></div></div></div><div class="mid-outer"><div class="mid-inner"><div class="mid"><asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><table style="width: 100%"><tr><td>
                                        your Name:</td><td style="width: 80%"><asp:TextBox ID="TextBox_Name" runat="server" CssClass="TextBox" Width="50%"></asp:TextBox><asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="TextBox_Name"
                                            ErrorMessage="please Inter Your Name" ValidationGroup="4546">*</asp:RequiredFieldValidator><Ajax:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender1" runat="server" TargetControlID="TextBox_Name"
                                            WatermarkCssClass="WaterMark" WatermarkText="Inter Your Name"></Ajax:TextBoxWatermarkExtender></td></tr><tr style="color: #000000"><td>
                                        EMail:</td><td><asp:TextBox ID="TextBox_Email" runat="server" CssClass="TextBox" Width="50%"></asp:TextBox><asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="TextBox_Email"
                                            ErrorMessage="Please Enter Email Address Correctly" ValidationExpression="\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*"
                                            ValidationGroup="4546">*</asp:RegularExpressionValidator><Ajax:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender2" runat="server" TargetControlID="TextBox_Email"
                                            WatermarkCssClass="WaterMark" WatermarkText="Enter Your Email Address"></Ajax:TextBoxWatermarkExtender></td></tr><tr style="color: #000000"><td style="vertical-align: top">
                                        Your Comment:<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="TextBox_Comment"
                                            ErrorMessage="Please Enter Your Comment" ValidationGroup="4546">*</asp:RequiredFieldValidator></td><td style="color: #000000"><asp:TextBox ID="TextBox_Comment" runat="server" CssClass="TextBox" Height="74px"
                                            TextMode="MultiLine" Width="98%"></asp:TextBox></td></tr><tr><td colspan="2"><asp:ValidationSummary ID="ValidationSummary1" runat="server" Style="float: right"
                                            ValidationGroup="4546" /><Ajax:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender3" runat="server" TargetControlID="TextBox_Comment"
                                            WatermarkCssClass="WaterMark" WatermarkText="Enter Your Comment"></Ajax:TextBoxWatermarkExtender></td></tr><tr><td colspan="2" style="text-align: center"><asp:Button ID="Button_Save" runat="server" CssClass="Button" OnClick="Button_Save_Click"
                                            Text="Save" ValidationGroup="4546" /><br /><Ajax:ConfirmButtonExtender ID="ConfirmButtonExtender1" runat="server" ConfirmText="Are You Sure for Saving"
                                            TargetControlID="Button_Save"></Ajax:ConfirmButtonExtender><asp:SqlDataSource ID="SqlDataSource_EnterMenuComments" runat="server" ConnectionString="<%$ ConnectionStrings:LocalSqlServer1 %>"
                                            InsertCommand="Menu_InsertComments" InsertCommandType="StoredProcedure" OnInserted="SqlDataSource_EnterMenuComments_Inserted"
                                            ProviderName="<%$ ConnectionStrings:LocalSqlServer.ProviderName %>"><InsertParameters><asp:ControlParameter ControlID="TextBox_Name" Name="AddedBy" PropertyName="Text"
                                                    Type="String" /><asp:ControlParameter ControlID="TextBox_Email" Name="AddedByEmail" PropertyName="Text"
                                                    Type="String" /><asp:Parameter Name="AddedByIP" Type="String" /><asp:Parameter Name="MenuID" Type="Int32" /><asp:ControlParameter ControlID="TextBox_Comment" Name="Body" PropertyName="Text"
                                                    Type="String" /></InsertParameters></asp:SqlDataSource></td></tr><tr><td colspan="2" style="text-align: center"><asp:Label ID="Label_Message" runat="server" ForeColor="Blue"></asp:Label></td></tr></table></ContentTemplate><Triggers><asp:PostBackTrigger ControlID="Button_Save"></asp:PostBackTrigger></Triggers></asp:UpdatePanel></div></div></div><div class="bottom-outer"><div class="bottom-inner"><div class="bottom"></div></div></div></div></div></asp:Content>

Master Page Code:

<table><tr><td style="width:217px; height:200px" ><asp:Panel runat="server"><asp:UpdatePanel id="UpdatePanel1" runat="server"><ContentTemplate><asp:Timer ID="Timer1" runat="server" Interval="2000" ontick="Timer1_Tick" ></asp:Timer><asp:AdRotator ID="AdRotator1" runat="server" Height="200px" Width="217px" BorderColor="Blue" /></ContentTemplate></asp:UpdatePanel></asp:Panel></td></tr></table><asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager><asp:contentplaceholder id="ContentPlaceHolderMain" runat="server" ></asp:contentplaceholder>

and in code behind of master page in page_load and Timer Tick i use this code:

        AdRotator1.DataSource = FetchAdsFromDB();
        AdRotator1.DataBind();

please help me for solving this problem.

thanks regard