Thank you for writing.
First I want to clarify that our themes work only with RadControls and does not apply to standard MS controls. Now, the load you saw is just the Load event of the Form. You can use it there, you can put it in the Form's constructor, or on a button click, it is up to you, so you don't need to inherit the form to apply a theme to it.
I hope that you find this information useful. Should you have any other questions, do not hesitate to contact us.
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