Annuler la prise de focus d'une Form 'surgissante'

Salut, encore une fois il faut passer par l'API Win32 :




public partial class Form1 : Form
{
    private const int SWP_NOACTIVATE = 0x0010;
    private const int SWP_SHOWWINDOW = 0x0040;

    [ System.Runtime.InteropServices.DllImport( "user32.dll", SetLastError = true ) ]
    private static extern bool SetWindowPos
    (
        IntPtr hWnd,
        IntPtr hWndInsertAfter,
        int x,
        int y,
        int cx,
        int cy,
        uint flags
    );

    public Form1( )
    {
        InitializeComponent( );

        Label lb = new Label( );
        lb.Location = new Point( 50, 50 );
        lb.BackColor = Color.AliceBlue;
        lb.MouseHover += delegate
        {
            Form f = new Form( );
            //f.FormBorderStyle = FormBorderStyle.FixedToolWindow;
            //f.ShowInTaskbar = false;
            Rectangle r = lb.RectangleToScreen( lb.ClientRectangle );

            SetWindowPos
            (
                f.Handle,
                IntPtr.Zero,
                r.Right + 10,
                r.Top - 10,
                150,
                100,
                SWP_NOACTIVATE | SWP_SHOWWINDOW
            );

            f.Visible = true; // Sinon 'Visible' reste false.
        };

        this.Controls.Add( lb );
    }
}