MissionPlanner.GridUI.map_MouseMove C# (CSharp) Method

        private void map_MouseMove(object sender, MouseEventArgs e)
        {
            PointLatLng point = map.FromLocalToLatLng(e.X, e.Y);
            currentMousePosition = point;

            if (MouseDownStart == point)
                return;

            if (!isMouseDown)
            {
                // update mouse pos display
                //SetMouseDisplay(point.Lat, point.Lng, 0);
            }

            //draging
            if (e.Button == MouseButtons.Left && isMouseDown)
            {
                isMouseDraging = true;

                if (CurrentGMapMarker != null)
                {
                    if (CurrentGMapMarkerIndex == -1)
                    {
                        isMouseDraging = false;
                        return;
                    }

                    PointLatLng pnew = map.FromLocalToLatLng(e.X, e.Y);

                    CurrentGMapMarker.Position = pnew;

                    list[CurrentGMapMarkerIndex] = new PointLatLngAlt(pnew);
                    domainUpDown1_ValueChanged(sender, e);
                }
                else // left click pan
                {
                    double latdif = MouseDownStart.Lat - point.Lat;
                    double lngdif = MouseDownStart.Lng - point.Lng;

                    try
                    {
                        lock (thisLock)
                        {
                            map.Position = new PointLatLng(map.Position.Lat + latdif, map.Position.Lng + lngdif);
                        }
                    }
                    catch { }
                }
            }
        }