Opening a dialog after closing an OpenFileDialog

[axx0]

So, I wish to:

1. Open an OpenFileDialog
2. After closing the OpenFileDialog immediately open another custom dialog

Here is my code:

using Modern.Forms;
using System.Drawing;

namespace ModernFormsApp1
{
    public partial class MainForm : Form
    {
        public MainForm()
        {
            this.Shown += async (_, _) =>
            {
                var ofd1 = new OpenFileDialog
                {
                    Title = "Open this file 1"
                };
                await ofd1.ShowDialog(this);

                await new DialogForm().ShowDialog(this);
            };
        }
    }

    public class DialogForm : Form
    {
        public DialogForm()
        {
            Text = "Dialog Form";
            Size = new Size(500, 250);

            var button3 = Controls.Add(new Button
            {
                Text = "DialogResult.Abort button",
                Left = 10,
                Top = 124,
                Width = 250,
                DialogResult = DialogResult.Abort
            });

            var button4 = Controls.Add(new Button
            {
                Text = "DialogResult.None button",
                Left = 10,
                Top = 164,
                Width = 250,
                DialogResult = DialogResult.None
            });
        }
    }
}

When I run the code the OpenFileDialog is opened, but when I close it I get a blank dialog screen:

However when I change the order of dialogs (first opening the custom dialog and then the OpenFileDialog) it runs ok.

What am I doing wrong?