Temporary focus for a popup?

Question

Hi, this is NOT URGENT, just a little brain teaser I have come upon myself.
I have a calendar-like component that I want to display on a popup. The user may open it (with a button) and choose something with the mouse (which hides the popup and fires an event). No problem there.
In the interest of not requiring mouse use (a big deal with me), I put in the handling value various keystrokes (<arrows/pageup/pagedn> move around; <enter> or <space> make selection; <escape> closes without selection, etc.). But I cannot figure out how to get the keystrokes delivered to my component because I can't seem to understand the temporary focus situation with popups.
I have tried writing my own JPopupMenu and Popup implementations, tried to manually move focus around, tried tweaking around with the MenuSelectionManager to see if it is eating my keystrokes, but I can't get it to work, and I know that there must be something much simpler that I am not seeing.
BTW, I am trying to not have to muck with the Input/Action Maps of the window (or of any ancestor component higher than the popup itself), though I have considered that I could change them when popup opens and restore them when popup closes. Like I said, there must be something much simpler, right?
I wrote a small sample case, which I will include in case anyone cares to give this a look.
SimplePanel just uses the arrow keys to change a Label among {N,E,S,W} values. It has a main that sticks it in a frame. The arrow key cause the label to change.
SimplePopup provides a button that opens a JPopupMenu containing a SimplePanel. (To keep it super simple, I haven't even included a way to close the popup.) User can open the popup by hitting <space> on the focused button, but cannot manipulate the SimplePanel using the arrow keys.
(I will post the code in separate messages)
Thanks,
/Mel

Answer 1

I have a solution -- add a KeyEventPostProcessor that redispatches the KeyEvents to the component on the popup. For the example, I just implemented KeyEventPostProcessor in this class. Hurray for 1.4!!!
My question from before still stands though: isn't there a simpler way to do this!??! Furthermore, why shouldn't this be the default behavior to begin with? (i.e. when a popup is opened on a window the popup becomes a temporarily focus root; when the popup is closed the (permanent) focus reverts to whoever had it before...)
/Mel
class SimplePopup extends JPopupMenu implements KeyEventPostProcessor
   SimplePanel content = null;
   SimplePopup(SimplePanel content)
      this.content = content;
      this.add(content);
   public boolean postProcessKeyEvent(KeyEvent e)
      if (this.isVisible())
         KeyboardFocusManager.getCurrentKeyboardFocusManager().redispatchEvent(this.content, e);
      return false;
   public void setVisible(boolean b)
      super.setVisible(b);
      if (b)
         KeyboardFocusManager.getCurrentKeyboardFocusManager().addKeyEventPostProcessor(this);
      else
         KeyboardFocusManager.getCurrentKeyboardFocusManager().removeKeyEventPostProcessor(this);
   public static void main(String[] args)
      JFrame frame = new JFrame();
      JPanel extraroom = new JPanel();
      extraroom.setBorder(new EmptyBorder(50,50,50,50));
      final JButton button = new JButton("show it");
      final SimplePanel spanel = new SimplePanel();
      final SimplePopup popupmenu = new SimplePopup(spanel);
      button.addActionListener(new ActionListener()
                                      public void actionPerformed(ActionEvent e)
                                         Point point = new Point(2, 2 + button.getBounds().height);
                                         Component window = SwingUtilities.getWindowAncestor(button);
                                         point = SwingUtilities.convertPoint(button,point,window);
                                         popupmenu.setLocation(point);
                                         popupmenu.setVisible(true);
      extraroom.add(button);
      frame.getContentPane().add(extraroom);
      frame.pack();
      frame.show();
} // end class SimplePopup