Alsing.Windows.Forms.CoreLib.SplitViewControl.Vertical_MouseMove C# (CSharp) Метод

        private void Vertical_MouseMove(object sender, MouseEventArgs e)
        {
            if (Action == SizeAction.SizeV && e.Button == MouseButtons.Left)
            {
                Point start;
                int x = e.X;
                int y = e.Y;

                if (x + Vertical.Left > Width - 4)
                    x = Width - 4 - Vertical.Left;
                if (x + Vertical.Left < 0)
                    x = 0 - Vertical.Left;


                if (!FirstTime)
                {
                    start = PointToScreen(Location);
                    start.X += PrevPos.X + Vertical.Location.X;
                    ControlPaint.FillReversibleRectangle(new Rectangle(start.X, start.Y, 3, Height), Color.Black);
                }
                else
                    FirstTime = false;

                start = PointToScreen(Location);
                start.X += x + Vertical.Location.X;
                ControlPaint.FillReversibleRectangle(new Rectangle(start.X, start.Y, 3, Height), Color.Black);

                PrevPos = new Point(x, y);
            }
        }