Hi Alexandre,
Thank you for the logged feature request.
We will track the demand for this feature and plan accordingly our future development plans.
What could be done as a workaround until the feature is released is to use some custom JavaScript in order to handle the generic (wheel) event of the input element used by the NumericTextBox and stop its propagation. Please check the following example demonstrating such approach:
https://stackblitz.com/edit/angular-5lbaf4-e4tgdj?file=app/app.component.ts
Regards,
Svetlin
Progress Telerik