How to set/change/remove focus style on a Button in C#?

Question

I have a couple of buttons of which I modified how they look. I have set them as flat buttons with a background and a custom border so they look all pretty and nothing like

Answer 1

Make a custom button:

public partial class CustomButton: Button
{
    public ButtonPageButton()
    {
        InitializeComponent();

        this.SetStyle(ControlStyles.Selectable, false);
    }
}

That'll get rid of that annoying border! ;-)