// Mouse down event.
private void pictureBox_MouseDown(object sender, MouseEventArgs e)
{
// Check to see if the right mouse button was the button that was clicked.
if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
isMouseScrolling = true;
// Set the location of the initial mouse click.
map.SetMouseScrollX(e.X);
map.SetMouseScrollY(e.Y);
}
}