C#

private Point mousePos;
private Point panelPos;
private bool isDragging;

private void panel1_MouseDown(object sender, MouseEventArgs e)
{
    if(e.Button == MouseButtons.Left)
    {
        isDragging = true;
        Cursor.Current = Cursors.Hand;
        mousePos = panel1.PointToScreen(e.Location);
        panelPos = panel1.Location;
    }
    
}

private void panel1_MouseUp(object sender, MouseEventArgs e)
{
     if(isDragging)
    {
        isDragging = false;
        Cursor.Current = Cursors.Default;
    }
}

private void panel1_MouseMove(object sender, MouseEventArgs e)
{
    if (!isDragging) return;
    Point point = panel1.PointToScreen(e.Location);
    panel1.Left = panelPos.X + point.X - mousePos.X;
    panel1.Top = panelPos.Y + point.Y - mousePos.Y;
}

using System;
using System.Runtime.InteropServices;

namespace WinAPI
{
	public class AnimateWindowAPI
	{
		public const int AW_HIDE		= 0x10000;
		public const int AW_ACTIVATE		= 0x20000;
		public const int AW_SLIDE		= 0x40000;
		public const int AW_BLEND		= 0x80000;
		public const int AW_HOR_POSITIVE	= 0x00000001;
		public const int AW_HOR_NEGATIVE	= 0x00000002;
		public const int AW_VER_POSITIVE	= 0x00000004;
		public const int AW_VER_NEGATIVE	= 0x00000008;
		public const int AW_CENTER		= 0x00000010;

		[DllImport("user32.dll", CharSet = CharSet.Auto)]
		public static extern int AnimateWindow(IntPtr hWnd, int dwTime, int dwFlags);
	}
}

using WinAPI;
private void Form1_Shown(object sender, EventArgs e)
{
	int flags = AnimateWindowAPI.AW_ACTIVATE|AnimateWindowAPI.AW_BLEND;
	AnimateWindowAPI.AnimateWindow(this.Handle, 3000, flags);
	Show();
}