Where is the extra space coming from?

I have extra space on the right and bottom of my page shown with red arrows in the attached picture. Where is it coming from?

My code:

public class StartPage : ContentPage
{
    public StartPage ()
    {
        BoxView topS = new BoxView {
            VerticalOptions = LayoutOptions.FillAndExpand
        };
        Button playB = new Button {
            Text = "Play",
            TextColor = Color.Black
        };
        Button optionsB = new Button {
            Text = "Options",
            TextColor = Color.Black
        };
        Button helpB = new Button {
            Image = (FileImageSource)ImageSource.FromFile("help.png")
        };
        BoxView midS = new BoxView {
            HorizontalOptions = LayoutOptions.FillAndExpand
        };
        Button infoB = new Button {
            Image = (FileImageSource)ImageSource.FromFile("info.png")
        };
        StackLayout bottomSL = new StackLayout {
            Orientation = StackOrientation.Horizontal,
            VerticalOptions = LayoutOptions.EndAndExpand,
            Children = {
                helpB, midS, infoB
            }
        };
        Content = new StackLayout {
            Children = {
                topS, playB, optionsB, bottomSL
            }
        };
    }
}