sbool mouseEventIsInBorder(MouseEvent e) swing {
  var c = optCast JComponent(e.getComponent());
  if (c == null) false;
  var border = c.getBorder();
  if (border == null) false;
  Insets insets = border.getBorderInsets(c);
  int x = e.getX(), y = e.getY();
  int w = c.getWidth(), h = c.getHeight();
  bool result = x < insets.left
    || x >= w-insets.right
    || y < insets.top
    || y >= h-insets.bottom;
  printVars ifdef mouseEventIsInBorder_debug("mouseEventIsInBorder " + result, +insets, +w, +h, +x, +y);
  ret result;
}

Began life as a copy of #1033465