How to disable the visual style?

Hello Ivan,

I'm afraid that the only way to achieve the desired approach is to modify the control template of RadNumericUpDown. At the moment focused state of RadNumericUpDown is designed to be always 1px and it is not template bound. We will consider your suggestion to add TemplateBinding for our control's focus state in order to make its customization easier.

Let me know if you need any further help with template customization.

Regards,
Masha
Telerik