Steps to reproduce:
1. Drag a page view to a form and add two pages to it.
2. Add a button on the first page.
3. Drag a button to the form and in its Click event handler add code to change the selected page of the page view to the second one.
4. Add an event handler for the Enter event of the button on the first page.
Run the project and when you click the button to change the page you will see that the button on the first page gets the focus.