sbool mouseEventIsInBorder(MouseEvent e) swing {
  Component c = e.getComponent();
  Border border = c.getBorder();
  if (border == null) false;
  Insets insets = border.getInsets();
  ret e.getX() < insets.left
    || e.getX() >= c.getWidth()-insets.right
    || e.getY() < insets.top
    || e.getY() >= c.getHeight()-insets.bottom;
}