JFrameがアクティブであるかどうかでテキスト選択ハイライト色を変更する

class FocusOwnerCaret extends DefaultCaret {
  private static final Color COLOR = Color.GRAY.brighter();
  private static final HighlightPainter NO_FOCUS_PAINTER =
      new DefaultHighlightPainter(COLOR);

  @Override public void focusLost(FocusEvent e) {
    super.focusLost(e);
    updateSelectionHighlightPainter();
  }

  @Override public void focusGained(FocusEvent e) {
    super.focusGained(e);
    updateSelectionHighlightPainter();
  }

  private void updateSelectionHighlightPainter() {
    setSelectionVisible(false); // removeHighlight
    setSelectionVisible(true); // addHighlight
  }

  @Override protected Highlighter.HighlightPainter getSelectionPainter() {
    JTextComponent c = getComponent();
    Container w = c.getTopLevelAncestor();
    // boolean isFocused = w instanceof Window && ((Window) w).isFocused();
    boolean isActive = w instanceof Window && ((Window) w).isActive();
    return c.hasFocus() && isActive ? super.getSelectionPainter() : NO_FOCUS_PAINTER;
    // https://ateraimemo.com/Swing/CaretSelectionHighlight.html
    // return c.hasFocus() ? super.getSelectionPainter() : NO_FOCUS_PAINTER;
  }
}