Не могу заскриптовать моему checkbox1 изменения topmost

    public static class FormsHelper
    {
        public static Action<bool> SetTopMost;
    }
    public class Form1 : Form
    {
        public Form1()
        {
            FormsHelper.SetTopMost += SetTopMost;
        }
        ~Form1()
        {
            FormsHelper.SetTopMost -= SetTopMost;
        }
        private void SetTopMost(bool value) => TopMost = value;
    }

    public static class FormsHelper
    {
        public static void SetTopMost(bool value)
        {
            foreach (var form in Application.OpenForms)
            {
                (form as Form).TopMost = value;
            }    
        }
    }

(s, e) = >
{
     FormsHelper.SetTopMost((s as CheckBox).Checked);
};

            bool value = (s as CheckBox).Checked;
            foreach (var form in Application.OpenForms)
            {
                (form as Form).TopMost = value;
            }

            bool value = (sender as CheckBox).Checked;
            foreach (var form in System.Windows.Forms.Application.OpenForms)
            {
                (form as Form).TopMost = value;
            }