Hello El Barto,
Can you try restarting the application, and let us know if the problems still persist? If you're still experiencing problems you'll need to map the template for LoginForm and LoginControl in the backend by going to Administration->Settings->Advanced->Controls>ViewMap->Create new and fill in the fields accordingly(all without the quotes):
LayoutTemplatePath: "relative path to your custom LoginControl.ascx "
I've also attached a screenshot for your reference. Please do not hesitate to let us know if you have any additional questions.
the Telerik team
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