Show PopUp Form without stealing focus

I am doing the same thing that this => Show a Form without stealing focus?

I'm using a Form to show notifications (it appears at the bottom right of the screen), but when I show this form it steals the focus from my software and computer. Is there a way to show this "notification" form without stealing focus?

I have tried all solution but when my form is open i loose the focus in all my computer :

My Notification Class :

/// <summary>
/// Class to sent Notification like Skype/Outlook
/// </summary>
public partial class Notification : Form
{
    private static readonly List<Notification> OpenNotifications = new List<Notification>();
    private readonly FormAnimator _animator;

    public Notification(...)
    {
        InitializeComponent();
        //Other...
    }

    public void Notification_Shown(object sender, EventArgs e)
    {
         // Close the form by sliding down.
        _animator.Duration = 0;
        _animator.Direction = FormAnimator.AnimationDirection.Down;
    }
    
    protected override bool ShowWithoutActivation
    {
       get { return true; }
    }
    
    protected override CreateParams CreateParams
    {
      get
          {
            CreateParams baseParams = base.CreateParams;
            const int WS_EX_NOACTIVATE = 0x08000000;
            const int WS_EX_TOOLWINDOW = 0x00000080;
            baseParams.ExStyle |= ( int )( WS_EX_NOACTIVATE | WS_EX_TOOLWINDOW );
            return baseParams;
          }
   }
    //Other Functions
}

}

My InitializeComponent() of Notification From (TopMost is false) :

    private void InitializeComponent()
    {
        //OTHER
        this.lifeTimer.Tick += new System.EventHandler(this.lifeTimer_Tick);
        this.Controls.Add(this.labelTitle);
        this.Controls.Add(this.labelBody);
        this.TopMost = false;
        this.FormClosed += new System.Windows.Forms.FormClosedEventHandler(this.Notification_FormClosed);
        this.Load += new System.EventHandler(this.Notification_Load);
        this.Shown += new System.EventHandler(this.Notification_Shown);
        this.Click += new System.EventHandler(this.Notification_Click);
        ((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
        this.ResumeLayout(false);
    }

My Notification form is open using Show :

        Notification toastNotification = new Notification(...);
        toastNotification.Show();

I know it's a duplicate but i really need your help , thank you :)