I tried to theme the look of the ValidatorCalloutExtender but when I try to apply the custom theme using the CssClass property (as mentioned in the docs), I get the following error on the page:
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Type 'AjaxControlToolkit.ValidatorCalloutExtender' does not have a public property named 'CssClass'.
Source Error:
Line 21: ErrorMessage="Please enter your user name."
Line 22: ControlToValidate="tbUserName" Display="None" />
Line 23: <ajax:ValidatorCalloutExtender ID="vceUserName" runat="server"
Line 24: TargetControlID="validatorUserName" CssClass="validatorCallout" />
Line 25: </div>
Comments: This ticket was filed for a pre-15.1 version of AJAX Control Toolkit. If this is still an issue in v15.1 or later, please create a new inquiry.
Parser Error
Description: An error occurred during the parsing of a resource required to service this request. Please review the following specific parse error details and modify your source file appropriately.
Parser Error Message: Type 'AjaxControlToolkit.ValidatorCalloutExtender' does not have a public property named 'CssClass'.
Source Error:
Line 21: ErrorMessage="Please enter your user name."
Line 22: ControlToValidate="tbUserName" Display="None" />
Line 23: <ajax:ValidatorCalloutExtender ID="vceUserName" runat="server"
Line 24: TargetControlID="validatorUserName" CssClass="validatorCallout" />
Line 25: </div>
Comments: This ticket was filed for a pre-15.1 version of AJAX Control Toolkit. If this is still an issue in v15.1 or later, please create a new inquiry.