This issue can really be confusing. Formally, the form has focus-related properties, but in a very different way than controls.
The "focus" always means keyboard focus, and it is something functional for focusable controls, not forms. A form is activated or deactivated, and when it is activated, the focus goes to the control which was focused before is any.
So, you can handle the events when each control is focused, or, you rather need to handle the event
. Please see: