In order for the RadCaptcha to work correctly in a UserControl scenario, the UserControl must be loaded in the Page_Init, if created dynamically, or registered directly on the Page. So, please change your source code to load the control in the Page_Init, and see if you still get the same behavior. You can also call RadCaptcha.Validate(), and Page.Validate() methods before, checking the IsValid properties, just to be sure that the Validation has occurred. Here is a sample code:
We will do our best to improve the control in one of our future releases.
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