@Override
    public void mouseEntered(final MouseEvent e) {
      final Component component = e.getComponent();
      if (component instanceof AbstractButton) {
        final AbstractButton button = (AbstractButton) component;
        button.setBorderPainted(false);
      }
    }
A tab button similar in style to the one used in Google Chrome.
java/ui/src/main/java/com/google/security/zynamics/bindiff/gui/components/closeablebuttontab/TabButton.java