在主框架之外时，JMenuItem不调用动作侦听器

Question

I have a JMenuItem in a JMenu sub-menu on the right of the main frame.

When the sub-menu pops up it is displayed to the right of the main menu and is outside of the main frame.

When the menu item is selected with a mouse click in this state, an ActionEvent is not propogated to the action listener.

Interestingly keyboard selection with enter does result in the action listener being called.

When the main frame is expanded to fill the screen the sub-menu pops out to the left of the main menu and is thus inside the main frame.

In this situation the ActionEvent is propogated when the mouse is clicked in the menu item.

I added a mouse listener to the JMenuItem to debug it and I noticed that MOUSE_ENTERED and MOUSE_PRESSED events do occur but not MOUSE_RELEASED events which only occur when the JMenuItem is inside the main frame.

I am using Java 1.7.0_45 on Windows 7 (64 bit).

Has anybody come else encountered this issue?

Answer 1

Problem was caused by the following initialization code in our application which is a workaround for an issue in Java 6: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6770457

    // Workaround for issue
    // (http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6770457)
    PopupFactory.setSharedInstance(new PopupFactory() {

        @Override
        public Popup getPopup(Component owner, Component contents, int x, int y) {
            Window win = SwingUtilities.getWindowAncestor(owner);
            if (win.isActive()) {
                return super.getPopup(owner, contents, x, y);
            }
            return super.getPopup(JOptionPane.getRootFrame(), contents, x, y);
        }
    });
    // end fix

The solution was to modify the if statement as follows:

            if (win.isActive() || win.getClass().getName().equalsIgnoreCase("javax.swing.Popup$HeavyWeightWindow")) {

Hopefully this will be useful to somebody else.