title: Textbox using Calendar Extender losing value
body: <p>I have a textbox using a CalendarExtender and some other controls for validation, here's the code:</p>
  
  <pre><code>&lt;asp:TextBox runat="server" ID="txtPrazoData" MaxLength="10" Width="80" /&gt;
  &lt;ajax:CalendarExtender ID="cePrazoData" runat="server" TargetControlID="txtPrazoData" /&gt;
  
  &lt;ajax:MaskedEditValidator runat="server" ID="mevPrazoDataModal" ControlToValidate="txtPrazoData" InvalidValueMessage="&lt;%$ Resources:Base, DataInvalida %&gt;" InvalidValueBlurredMessage="*" Text="*" 
  ControlExtender="meePrazoData" ErrorMessage="*" EmptyValueMessage="&lt;%$ Resources:Base, CampoRequerido %&gt;"
  IsValidEmpty="false" EmptyValueBlurredText="*" ValidationGroup="GrpAcaoModal"&gt;*&lt;/ajax:MaskedEditValidator&gt;
  
  &lt;ajax:MaskedEditExtender runat="server" ID="meePrazoData" TargetControlID="txtPrazoData" Mask="99/99/9999" MaskType="Date"/&gt;
  &lt;ajax:ValidatorCalloutExtender ID="vcePrazoData" TargetControlID="mevPrazoDataModal" runat="server"/&gt;
  &lt;asp:CompareValidator ID="cvPrazoData" runat="server" ControlToValidate="txtPrazoData" Type="Date" Operator="DataTypeCheck" ErrorMessage="&lt;%$ Resources: Base, DataInvalida %&gt;" Display="None" ValidationGroup="GrpAcaoModal" /&gt;
  &lt;ajax:ValidatorCalloutExtender ID="vcePrazoDataCompare" runat="server" TargetControlID="cvPrazoData" /&gt;
  </code></pre>
  
  <p>When I select the textbox and pick a date from the calendar and then select another control of the form, the textbox simply loses it's value:
  <img src="https://i.stack.imgur.com/O04uB.png" alt="enter image description here"></p>
  
  <p>If I type the value instead of selecting it from the calendar, it doesn't disappear. There is no postback happening and the textbox has no TextChanged event or any other associated.
  If I try to do this using IE's compatibility mode, it works. If it helps, I'm using IE9 version 9.0.8112.16421.</p>