KeyStroke in InputMap for CTRL only must have CTRL_DOWN_MASK and CTRL_MASK (win10 only)

Question

I have a custom component (inherited from JComponent) and like to underline a link while holding CTRL pressed right like eclipse does. I decide to use InputMap and ActionMap for keypress/release feature.

I use this code to find the stroke:

stroke = KeyStroke.getKeyStroke("pressed CONTROL");

But it is wrong somehow. I debugged the processKeyBinding method of JComponent and find out that if i press CTRL a KeyStroke having modifier 130.

(this is my InputMap, arg0 is the incomming KeyStroke from the Keyboard)

I think 130 is the result of the addition of CTRL_DOWN_MASK who has code 128 and CTRL_MASK has code 2.

1. Why do i have to add theese modifiers?
2. Is this cross-platform?
3. Is there any official documentation?

Full example camickr requests:

public class Test extends JLabel {
    public static void main(String[] args) {
        final JFrame jf = new JFrame("Test");
        final Test label = new Test();
        jf.getContentPane().add(label);
        jf.setBounds(200, 200, 500, 500);
        jf.pack();
        jf.setVisible(true);
        label.grabFocus();
    }

    public Test() {
        super("Foobar");
        addBoldOnCtrl();
    }

    public void addBoldOnCtrl() {
        final KeyStroke onDown = KeyStroke.getKeyStroke(KeyEvent.VK_CONTROL, KeyEvent.CTRL_MASK + KeyEvent.CTRL_DOWN_MASK);
        final String onDownName = "react on ctrl";
        getInputMap().put(onDown, onDownName);
        getActionMap().put(onDownName, new AbstractAction() {

            @Override
            public void actionPerformed(ActionEvent e) {
                final Font f = getFont();
                setFont(new Font(f.getFontName(), f.getStyle(), f.getSize() + 2));
                repaint();
            }
        });
    }
}

Answer 1

1.Why do i have to add theese modifiers?

You don't have to add both modifiers, just the CTRL_DOWN_MASK.

So to create the KeyStroke you can use:

KeyStroke ks = KeyStroke.getKeyStroke("control CONTROL");

KeyStroke ks = KeyStroke.getKeyStroke(KeyEvent.VK_CONTROL, KeyEvent.CTRL_DOWN_MASK);

I don't know of any documentation that explicitly states you need to do this but the "modifier keys" are different than other keys on the keyboard.