private void dataGridView3_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {
            if (DGV_CmbEditing)
            {
                int Left, Top, Width, Height;
                Left = this.Left + tabControl1.TabPages[1].Left + dataGridView3.Left + 811;
                Top = this.Top + this.FontHeight + tabControl1.ItemSize.Height + tabControl1.TabPages[1].Top + dataGridView3.Top + e.CellBounds.Y + 13;
                Cursor.Position = new Point(Left, Top);
                Left = this.Left + tabControl1.TabPages[1].Left + dataGridView3.Left + 600;
                Top = this.Top + this.FontHeight + tabControl1.ItemSize.Height + tabControl1.TabPages[1].Top + dataGridView3.Top + e.CellBounds.Y;
                Width = e.CellBounds.Width;
                Height = e.CellBounds.Height;
                this.Cursor = new Cursor(Cursor.Current.Handle);
                Cursor.Clip = new Rectangle(Left, Top, Width, Height);
                DGV_CmbEditing = false;
            }
        }

        private void DGV_TextBox_Enter(object sender, EventArgs e)
        {
            ComboBox cmb_box = sender as ComboBox;
            int Left, Top, Width, Height;
            Left = this.Left + tabControl1.TabPages[1].Left + dataGridView3.Left + 600;
            Top = this.Top + this.FontHeight + tabControl1.ItemSize.Height + tabControl1.TabPages[1].Top + dataGridView3.Top + cmb_box.Bounds.Y;
            Width = cmb_box.Bounds.Width;
            Height = cmb_box.Bounds.Height;
            this.Cursor = new Cursor(Cursor.Current.Handle);
            Cursor.Clip = new Rectangle(Left, Top, Width, Height);
        }

private void dataGridView3_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
{           
   if (DGV_CmbEditing)
   {
	Point PointOnCell = new Point();
	PointOnCell.X = 810;
	PointOnCell.Y = this.Top + e.CellBounds.Y + 10;
	Cursor.Position = PointToScreen(PointOnCell);

	Rectangle CellRect = new Rectangle();
	CellRect.X = 600;
	CellRect.Y = this.Top + e.CellBounds.Y;
	CellRect.Width = e.CellBounds.Width;
	CellRect.Height = e.CellBounds.Height;
	this.Cursor = new Cursor(Cursor.Current.Handle);
	Cursor.Clip = RectangleToScreen(CellRect);

	DGV_CmbEditing = false;
   }
}