Name: sv35042 Date: 10/18/2002


FULL PRODUCT VERSION :
java version "1.4.0_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0_01-b03)
Java HotSpot(TM) Client VM (build 1.4.0_01-b03, mixed mode)


FULL OPERATING SYSTEM VERSION :

Windows NT Version 4.0

(Service Pack 6)


A DESCRIPTION OF THE PROBLEM :
Let a component "comp" be nested inside a JSplitPane "inner"
with VERTICAL_SPLIT mode. Let "inner" be nested inside a
JSplitPane "outer" with HORIZONTAL_SPLIT mode. Finally, add
a component listener to "comp".

With this setup, componentResized() on the listener is
called when the divider of "outer" is moved manually.
However, it is not called when the divider of "outer" is
moved completely to the left using the triangle at the top
of the divider.

The bug doesn't occur when the left component of "outer" is
a JPanel containing "comp" (this variant is commented out in
the example source code). It only occurs with the nested
JSplitPane. Also, a ComponentListener attached to "inner"
gets called correctly (see example source code).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create a JComponent "comp" (actual class doesn't matter;
the example source code uses a JScrollPane containing a
JList, but I've tested others too)

2. Create a JSplitPane "inner" with VERTICAL_SPLIT mode and
"comp" as the top component (bottom component doesn't matter)

3. Create a JSplitPane "outer" with HORIZONTAL_SPLIT mode
and "inner" as the left component (top component doesn't matter)

4. Add a component listener to "comp" and monitor the
componentResized() events

All of this is done in the provided example source code.


EXPECTED VERSUS ACTUAL BEHAVIOR :
Expected output of the example source code when the top
triangle of the horizontal split divider is clicked:

| inner resized
| comp resized

Actual output:

| inner resized


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;

import java.util.*;

public class SplitPaneDemo {
    private Vector listItems;
    private JList list;
    private JSplitPane outer;

    public SplitPaneDemo() {

        // set up a simple list embedded inside a scroll pane
        listItems = new Vector();
        listItems.add("Item 1");
        listItems.add("Item 2");
        list = new JList(listItems);
        list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        list.setSelectedIndex(0);
        JScrollPane comp = new JScrollPane(list);
        
        // --> variant 1: left side of outer JSplitPane is an inner JSplitPane
containing the list
        JSplitPane inner = new JSplitPane(JSplitPane.VERTICAL_SPLIT,
                                          comp, new JPanel());
        // <--
        
        // --> variant 2: left side of outer JSplitPane is a JPanel containing
the list
        //JPanel containerPane = new JPanel();
        //containerPane.setLayout(new BorderLayout());
        //containerPane.add(listScrollPane);
        // <--
        
        JPanel rightPanel = new JPanel();
        outer = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
                               inner, rightPanel);
        outer.setOneTouchExpandable(true);
        outer.setDividerLocation(150);

        //Provide minimum sizes for the two components in the split pane
        Dimension minimumSize = new Dimension(100, 50);
        comp.setMinimumSize(minimumSize);
        inner.setMinimumSize(minimumSize);
        rightPanel.setMinimumSize(minimumSize);

        //Provide a preferred size for the split pane
        outer.setPreferredSize(new Dimension(400, 200));
        inner.addComponentListener(new ComponentAdapter() {
         public void componentResized(ComponentEvent e) {
         System.out.println("inner resized");
         }
        });
        comp.addComponentListener(new ComponentAdapter() {
         public void componentResized(ComponentEvent e) {
         System.out.println("comp resized");
         }
        });
    }

    public JSplitPane getSplitPane() {
        return outer;
    }


    public static void main(String s[]) {
        JFrame frame = new JFrame("SplitPaneDemo");

        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {System.exit(0);}
        });

        SplitPaneDemo splitPaneDemo = new SplitPaneDemo();
        frame.getContentPane().add(splitPaneDemo.getSplitPane());
        frame.pack();
        frame.setVisible(true);
    }
}

---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Not easy. The problem is that in our real application the
component in question may appear inside other components
(not only JSplitPane) and may be moved from one container
(e.g. JPanel) to another (e.g. JSplitPane) at runtime. It
would probably still be possible to find a workaround by
always monitoring the parent component, but it would be
quite painful.

Note that we *must* be informed of resizing since we do some
native drawing in our component. We already use a layout
manager, but for the native part that doesn't help.
(Review ID: 158733)
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