sclass AutoComboBox2 extends JComboBox<Object> {
  F1<S, Collection<S>> entryMaker;
  
  *() { this(null); }
  
  *(F1<S, Collection<S>> *entryMaker) {
    setSelectedIndex(-1);
    setEditable(true);
    JTextField text = cast this.getEditor().getEditorComponent();
    text.setFocusable(true);

    text.addKeyListener(new KeyAdapter {
      public void /*keyPressed*/keyReleased(KeyEvent key) {
        if (key.getKeyCode() == KeyEvent.VK_ENTER) ret;
        
        if (key.getKeyCode() == KeyEvent.VK_ESCAPE) { hidePopup(); ret; }
        
        if (key.getKeyCode() == KeyEvent.VK_TAB /*&& key.getModifiers() == 0*/) {
          _print("Have tab event (modifiers=" + key.getModifiers() + ")");
          if ((key.getModifiers() & ActionEvent.SHIFT_MASK) == 0 && isPopupVisible()) {
            setSelectedIndex(0); // accept item
            hidePopup();
          } else // standard tab behavior
            swing_standardTabBehavior(key);
            
          ret;
        }
        
        JTextField tf = cast getEditor().getEditorComponent();
        if (tf.getCaretPosition() != l(tf.getText())) ret;
        String text = tf.getText();
    
        Vector list = new Vector(getSuggestions(text));
        if (nempty(list)) {
          setModel(new DefaultComboBoxModel(list));
          setSelectedIndex(-1);
          tf.setText(text); // necessary?
          showPopup();
        } else
          hidePopup();
      }
    });
      
    text.setFocusTraversalKeysEnabled(false);
  }
  
  Collection<S> getSuggestions(S text) {
    ret callF(entryMaker, text);
  }
}

Began life as a copy of #1007529