public RadForm1()
        {
            InitializeComponent();
            this.IsMdiContainer = true;

            RadForm form = new RadForm();
            form.Text = "Net Core WinForms MDI Child 1";
            form.MdiParent = this; 
            form.Show();

            form = new RadForm();
            form.Text = "Net Core WinForms MDI Child 2";
            form.MdiParent = this; 
            form.Show();

            form = new RadForm();
            form.Text = "Net Core WinForms MDI Child 3";
            form.MdiParent = this;
            form.Show();

            this.radMenuItem1.Shortcuts.Add(new RadShortcut(Keys.Control, Keys.X));
            this.radMenuItem1.Click += RadMenuItem1_Click;

            this.radMenuItem2.Shortcuts.Add(new RadShortcut(Keys.Control, Keys.A));
            this.radMenuItem2.Click += RadMenuItem2_Click;
        }

        private void RadMenuItem1_Click(object sender, EventArgs e)
        {
            RadMessageBox.Show("Ctrl+X");
        }

        private void RadMenuItem2_Click(object sender, EventArgs e)
        {
            RadMessageBox.Show("Ctrl+A");
        }