RE: Validator Callout Extender disabling controls after dismissal

i have a textbox (call it textbox 1) with a required field validator and a ajax callout extender. The callout extender displays/overlaps a nearby textbox (call it textbox2).  When I dismiss the callout extender or fix the validation error in the 1st textbox the area where the calloutextender overlapped textbox 2 is disabled. I cant figure out why this is happening. I dont have any custom css for the callout extender.

I am using asp.net 4.0 and version 4.1.7.123 of the ajax control toolkit.

Here is some sample code

<table><tr><td class="style2"><strong>SSN:</strong></td><td><asp:TextBox ID="tbSSN" runat="server" Width="120px" MaxLength="11" ToolTip="SSN"></asp:TextBox><ajaxToolkit:FilteredTextBoxExtender ID="FilteredTextBoxExtender7" runat="server"
                    Enabled="True" FilterType="Numbers, Custom" TargetControlID="tbSSN" ValidChars="-"></ajaxToolkit:FilteredTextBoxExtender><asp:RegularExpressionValidator ID="regexSSN" runat="server" SetFocusOnError="true"
                    Display="Dynamic" ErrorMessage="Invalid Format!" ControlToValidate="tbSSN" ValidationExpression="^(\d{3}-\d{2}-\d{4})|(\d{3}\d{2}\d{4})$"></asp:RegularExpressionValidator><ajaxToolkit:ValidatorCalloutExtender ID="ValidatorCalloutExtender7" runat="server"
                    TargetControlID="regexSSN"></ajaxToolkit:ValidatorCalloutExtender>&nbsp; <strong>Case Number:</strong><asp:TextBox ID="tbCaseNumber" Width="115px" runat="server" MaxLength="10"></asp:TextBox><br /><ajaxToolkit:FilteredTextBoxExtender ID="FilteredTextBoxExtender6" runat="server"
                    Enabled="True" FilterType="Numbers" TargetControlID="tbCaseNumber" ValidChars="/"></ajaxToolkit:FilteredTextBoxExtender><asp:RegularExpressionValidator runat="server" ID="regexCaseNumber" ErrorMessage="Invalid! Must be a minimum of 5 digits."
                    ControlToValidate="tbCaseNumber" Visible="true" Enabled="true" SetFocusOnError="true"
                    ValidationExpression="^[0-9]{5,10}$"></asp:RegularExpressionValidator><ajaxToolkit:ValidatorCalloutExtender ID="ValidatorCalloutExtender4" runat="server"
                    TargetControlID="regexCaseNumber"></ajaxToolkit:ValidatorCalloutExtender></td></tr></table>