Error with watermark control

OK, I found the reason. Because 2 atlas toolkit contorls use same textbox as target control.

So what's the solution for this issue?

<asp:Panel ID="Panel1" runat="server" CssClass="popupControl">
<atlas:UpdatePanel ID="UpdatePanel1" runat="server" Mode="Conditional" RenderMode="Inline">
<ContentTemplate>
<center>
<asp:Calendar ID="Calendar1" runat="server" BackColor="White" BorderColor="#999999"
CellPadding="1" DayNameFormat="Shortest" Font-Names="Verdana" Font-Size="8pt"
ForeColor="Black" Width="160px" OnSelectionChanged="Calendar1_SelectionChanged">
<SelectedDayStyle BackColor="#666666" Font-Bold="True" ForeColor="White" />
<TodayDayStyle BackColor="#CCCCCC" ForeColor="Black" />
<SelectorStyle BackColor="#CCCCCC" />
<WeekendDayStyle BackColor="#FFFFCC" />
<OtherMonthDayStyle ForeColor="#808080" />
<NextPrevStyle VerticalAlign="Bottom" />
<DayHeaderStyle BackColor="#CCCCCC" Font-Bold="True" Font-Size="7pt" />
<TitleStyle BackColor="#999999" BorderColor="Black" Font-Bold="True" />
</asp:Calendar>
</center>
<atlasToolkit:PopupControlExtender ID="PopupControlExtender1" runat="server">
<atlasToolkit:PopupControlProperties TargetControlID="textbox2" PopupControlID="Panel1"
Position="Bottom" />
</atlasToolkit:PopupControlExtender>
</ContentTemplate>
</atlas:UpdatePanel>
</asp:Panel>
<atlasToolkit:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender1" runat="server">
<atlasToolkit:TextBoxWatermarkProperties TargetControlID="textbox1" WatermarkText="Type Batch Name Here"
WatermarkCssClass="watermarked" />
<atlasToolkit:TextBoxWatermarkProperties TargetControlID="textbox2" WatermarkText="Format: DD/MM/YYYY"
WatermarkCssClass="watermarked" />
</atlasToolkit:TextBoxWatermarkExtender>

This can usually be solved by adding an ID to one/both of the Properties declarations.

Ex: <atlasToolkit:TextBoxWatermarkProperties ... id="MyId" />