Java Swing JSeparator in Menu incorrectly placed

Question

I have a problem when i want insert a separator with JSeparator for Java Swing application. In point of fact, I have this problem just when i run my program on Mac, i haven't it on windows or linux. The separator is incorrectly placed, the text is strikethrough. Does anyone know why?

My code :

JMenuItem fileItem = new JMenuItem("Close");
KeyStroke ...
fileItem.add(new JSeparator(JSeparator.HORIZONTAL),BorderLayout.LINE_START);

Screenshot : enter image description here

David Kroukamp · Accepted Answer · 2013-01-29T22:45:06.837

Basically your code right now shows that you are assuming JMenuItem has a default BorderLayout, which could be true (but I dont think so).

Though the root problem is you are adding the JSeparator to the JMenuItem when in fact you should add it to the JMenu which contains the various JMenuItems via JMenu#addSeparator(). See How to Use Separators for more.

You should be doing something like:

JMenu menu=new JMenu();

JMenuItem item1=new JMenuItem("something 1");
JMenuItem item2=new JMenuItem("something 1");

menu.add(item1);
menu.addSeparator();//lets add that separator
menu.add(item2);

giving you something like:

enter image description here

UPDATE:

Here is an example:

enter image description here

import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.SwingUtilities;

public class Test {

    public Test() {
        JFrame frame = new JFrame();
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);

        JMenuBar menuBar=new JMenuBar();

        JMenu menu = new JMenu("File");
        JMenu menu2 = new JMenu("Else");

        JMenuItem item1 = new JMenuItem("something 1");
        JMenuItem item2 = new JMenuItem("something 2");
        JMenuItem item3 = new JMenuItem("else 1");
        JMenuItem item4 = new JMenuItem("else 2");

        menu2.add(item3);
        menu2.addSeparator();//lets add that separator
        menu2.add(item4);

        menu.add(menu2);
        menu.add(item1);
        menu.addSeparator();//lets add that separator
        menu.add(item2);

        menuBar.add(menu);

        frame.setJMenuBar(menuBar);
        frame.pack();
        frame.setVisible(true);
    }

    public static void main(String args[]) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test();
            }
        });
    }
}

@Dan While thinking what Layout the JMenuItem would have to allow us to add more items like a `JSeparator` or something and it hit me we do it on the `JMenu` :P — David Kroukamp, Jan 29 '13 at 19:46
If i do that , the separator is placed at the beginning of menu. I put it right where I want it between "save as" and "close". — Tof, Jan 29 '13 at 19:48
@David No it's perfect! Sorry I didn't put in the right place between filemenu.add(saveAs) and filemenu.add(fileItemClose). Now it's good! :) 'filemenu.add(saveAs) filemenu.addSeparator() filemenu.add(fileItemClose)' — Tof, Jan 29 '13 at 20:03

Java Swing JSeparator in Menu incorrectly placed

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