Visual Studio Code – Why is my winforms project immediately closing?

When I was editing my project and tweaking it, I decided to test it, but it won’t run.
When I looked in the console, it closed with an exit code of 0.
Is it a Visual Studio bug? I’m on Visual Studio 2022, by the way.
If it is a code problem, here is the code on Form1:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Flipbook
{
    public partial class Form1 : Form
    {
        Graphics g;
        Pen p;
        Brush b;
        bool d = false;
        int tool = 1;
        int width = 10;
        Point m1;
        Point m2;
        int selectedframe = 0;
        public Form1()
        {
            InitializeComponent();
        }

        private void undoInCurrentPageToolStripMenuItem_Click(object sender, EventArgs e)
        {

        }

        private void redoInCurrentPageToolStripMenuItem_Click(object sender, EventArgs e)
        {

        }

        private void cutCurrentPageToolStripMenuItem_Click(object sender, EventArgs e)
        {

        }

        private void button2_Click(object sender, EventArgs e)
        {
            tool = 3;
        }

        private void button1_Click(object sender, EventArgs e)
        {
            tool = 1;
        }

        private void copyCurrentPageToolStripMenuItem_Click(object sender, EventArgs e)
        {

        }

        private void pastePageToolStripMenuItem1_Click(object sender, EventArgs e)
        {

        }

        private void addPageToolStripMenuItem_Click(object sender, EventArgs e)
        {
            imageList1.Images.Add(Flipbook.Properties.Resources.blank);
        }

        private void deleteThisPageToolStripMenuItem_Click(object sender, EventArgs e)
        {
            imageList1.Images.RemoveAt(selectedframe);
        }

        private void flipToTheNextPageToolStripMenuItem_Click(object sender, EventArgs e)
        {
            selectedframe++;
            pictureBox1.Refresh();
            pictureBox1.Image = imageList1.Images[selectedframe];
        }

        private void flipToThePreviousPageToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (!(selectedframe == 0))
            {
                selectedframe--;
                pictureBox1.Refresh();
                pictureBox1.Image = imageList1.Images[selectedframe];
            }
        }

        private void newAnimationToolStripMenuItem_Click(object sender, EventArgs e)
        {
            listView2.Items.Clear();
            listView2.Items.Add("", selectedframe);
            pictureBox1.Refresh();
            g = pictureBox1.CreateGraphics();
            p = new Pen(Color.Black, 1);
            b = new SolidBrush(Color.Black);
        }

        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }

        private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
        {
            d = true;
            m1 = e.Location;
        }

        private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
        {
            d = false;
        }

        private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
        {
            m2 = e.Location;
            p.Color = panel2.BackColor;
            p.Width = width;
            b = new SolidBrush(panel2.BackColor);
            if (d)
            {
                switch (tool)
                {
                    case 1:
                        g.DrawLine(p, m1, m2);
                        break;
                    case 2:
                        g.FillEllipse(b, e.X, e.Y, width, width);
                        break;
                    case 3:
                        g.FillEllipse(new SolidBrush(Color.White), e.X, e.Y, width, width);
                        break;
                }
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            tool = 2;
        }

        private void numericUpDown1_ValueChanged(object sender, EventArgs e)
        {
            width = (int)numericUpDown1.Value;
        }

        private void panel2_Click(object sender, EventArgs e)
        {
            ColorDialog cd = new ColorDialog();
            if (cd.ShowDialog() == DialogResult.OK)
            {
                panel2.BackColor = cd.Color;
            }
        }
    }
}

Program Class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Flipbook
{
    internal static class Program
    {
        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

I tried to reload visual studio, tweak some settings, and I was expecting it to run normally, but the program immediately closed.