Constraints do not work for subview

[LuoyeAn]

hi, i am meeting a constraints issue.

            var cyan = new UIView { BackgroundColor = UIColor.Cyan };
            var red = new UIView { BackgroundColor = UIColor.Red };

            View.AddSubviews(cyan, red);
            View.SubviewsDoNotTranslateAutoresizingMaskIntoConstraints();

            View.AddConstraints(cyan.FullSizeOf(View, 20));
            View.AddConstraints(red.FullSizeOf(cyan, new Margins(10, 30)));

above code is working.

for my ios project, i want to set the red view as a subview for cyan view. so i changed the code to

            var cyan = new UIView { BackgroundColor = UIColor.Cyan };
            var red = new UIView { BackgroundColor = UIColor.Red };

            View.AddSubview(cyan);
                        cyan.AddSubview(red);

            View.SubviewsDoNotTranslateAutoresizingMaskIntoConstraints();

            View.AddConstraints(cyan.FullSizeOf(View, 20));
                        cyan.AddConstraints(red.FullSizeOf(cyan, new Margins(10, 30)));

The constraints are not woking. then i do not see the red view.

Is something wrong for me? Please check this. Thanks!

[LuoyeAn]

44 Made a pr to fix this issue.