Возможен ли фикс затемнения

    private void button1_Click(object sender, EventArgs e)
    {
        // take a screenshot of the form and darken it:
        Bitmap bmp = new Bitmap(this.ClientRectangle.Width, this.ClientRectangle.Height);
        using (Graphics G = Graphics.FromImage(bmp))
        {
            G.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceOver;
            G.CopyFromScreen(this.PointToScreen(new Point(0, 0)), new Point(0, 0), this.ClientRectangle.Size);
            double percent = 0.60;
            Color darken = Color.FromArgb((int)(255 * percent), Color.Black);
            using (Brush brsh = new SolidBrush(darken))
            {
                G.FillRectangle(brsh, this.ClientRectangle);
            }
        }
 
        // put the darkened screenshot into a Panel and bring it to the front:
        using (Panel p = new Panel())
        {
            p.Location = new Point(0, 0);
            p.Size = this.ClientRectangle.Size;
            p.BackgroundImage = bmp;
            this.Controls.Add(p);
            p.BringToFront();
 
            // display your dialog somehow:
            Form frm = new Form();
            frm.StartPosition = FormStartPosition.CenterParent;
            frm.ShowDialog(this);
        } // panel will be disposed and the form will "lighten" again...
    }

p.Dispose();

private void button1_Click(object sender, EventArgs e)
        {
            using (Form frm = new Form())
            {
                frm.StartPosition = FormStartPosition.CenterParent;
                ShowDialogOnDarkBG(frm, this);
            }
        }
 
 static DialogResult ShowDialogOnDarkBG(Form dialogForm, Form mainForm)
        {
            using (Form darkOverlay = new Form())
            {
                darkOverlay.BackColor = Color.Black;
                darkOverlay.Opacity = 0.6;
                darkOverlay.StartPosition = FormStartPosition.Manual;
                darkOverlay.FormBorderStyle = FormBorderStyle.None;
                darkOverlay.Location = mainForm.PointToScreen(mainForm.ClientRectangle.Location);
                darkOverlay.Size = mainForm.ClientRectangle.Size;
                darkOverlay.Show(mainForm);
                return dialogForm.ShowDialog(darkOverlay);
            }
        }