public override void Layout()
{
base.Layout();
var width = this.Bounds.Size.Width;
var padding = new CGSize(10, 10);
var p = new CGPoint(width - padding.Width, 0);
cancelButton.SizeToFit();
p = p.Move(-cancelButton.Frame.Size.Width, padding.Height);
cancelButton.SetFrameOrigin(p);
chooseButton.SizeToFit();
p = p.Move(-chooseButton.Frame.Size.Width, 0);
chooseButton.SetFrameOrigin(p);
p.X = padding.Width;
systemFontButton.SizeToFit();
systemFontButton.SetFrameOrigin(p);
line.Frame = new CGRect(0, Bounds.Size.Height - 1, width, 1);
}