public void paint(Graphics g) {
super.paint(g);
if (!isEditing) return;
Dimension psize = getPreferredSize();
if (isFocused) g.setColor(Color.yellow);
else g.setColor(Color.green);
g.drawLine(0, 0, psize.width, 0);
g.drawLine(0, 0, 0, psize.height);
g.drawLine(0, psize.height - 1, psize.width - 1, psize.height - 1);
g.drawLine(psize.width - 1, 0, psize.width - 1, psize.height - 1);
}
