Question

Is there a way to make a UserControl unfocussable?

EDIT: So SetStyle(ControlStyles.Selectable, false)

is the way to go. But still there is difference to Control. If you inherit form Control the initial control does not lose focus. But after clicking on your control that is derived from UserControl and

ControlStyles.Selectable 

is applied focus is removed from initial control.

Answer 1

In your constructor after InitializeComponent() you need to call SetStyle and set the ControlStyles.Selectable style to false:

SetStyle(ControlStyles.Selectable, false);