AnimateWindow have no effect on maximazed form c#

I'm trying to animate the form on loading. I used AnimateWindow:

 public partial class AdministrationMDI : Form
{
    [DllImport("user32")]
    static extern bool AnimateWindow(IntPtr hwnd, int time, AnimateWindowFlags flags);

    public AdministrationMDI()
    {

        InitializeComponent();

    }
    enum AnimateWindowFlags : uint
    {
        AW_HOR_POSITIVE = 0x00000001,
        AW_HOR_NEGATIVE = 0x00000002,
        AW_VER_POSITIVE = 0x00000004,
        AW_VER_NEGATIVE = 0x00000008,
        AW_CENTER = 0x00000010,
        AW_HIDE = 0x00010000,
        AW_ACTIVATE = 0x00020000,
        AW_SLIDE = 0x00040000,
        AW_BLEND = 0x00080000
    }

And i call it on form_load:

private void AdministrationMDI_Load(object sender, EventArgs e)
    {

        AnimateWindow(this.Handle, 1000, AnimateWindowFlags.AW_BLEND);

    }

but when i put windowstate property on 'maximized' , the animation doesn't work. Is there any solution to resolve this ? Thank you!

protected override void OnLoad(EventArgs e)
{
    this.Visible = false;
    this.Opacity = 1;
    AnimateWindow(this.Handle, 1000, AnimateWindowFlags.AW_BLEND);
    base.OnLoad(e);
}

You can try this code, paste it into your Form class. It works in the project that I'm working on.I hope that these help to you.