Name: jk109818 Date: 07/14/2003


FULL PRODUCT VERSION :
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2-b28)
Java HotSpot(TM) Client VM (build 1.4.2-b28, mixed mode)

This behavior is in older SDKs also.

FULL OS VERSION :
Microsoft Windows 2000 [Version 5.00.2195]

This behavior is not OS-specific.


A DESCRIPTION OF THE PROBLEM :
I have a GUI that has scrollable (JTextArea) components
stacked inside a panel which is also scrollable.
This is a fairly normal "form" interface.

The mouse wheel scrolls the whole outer panel fine,
unless it is over one of the JTextArea components.
If so, it simply stops -- I assume the JTextArea is now
getting the mouseWheelMoved events.

This would be ok, except that
it happens even if the JTextArea is not currently
scrollable. (In other words, it has no scroll bars
because it has few enough enough lines that it does
not need to scroll.)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1) run the attached code sample
2) shrink the GUI so that it has scroll bars
3) use the mouse-wheel to scroll

Scrolling will work unless you position your
mouse on a one of the JTextArea fields.


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The whole pane should scroll, instead of the JTextArea --
if the JTextArea does not have enough lines to need scrolling.

Alternatively, you could behave the same way IE does -- scroll
the field until you reach the top (or bottom), then scroll
the form. (That is, the same way this bug-submission form works).

ACTUAL -
The scrolling stopped once the JTextArea was scrolled
under the cursor.


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import java.awt.*;
import javax.swing.*;
import javax.swing.border.TitledBorder;

public class ScrollTest
{
   public static void main (String[] args)
   {
      JPanel panel = new JPanel (new GridLayout (0, 1));
      panel.setPreferredSize (new Dimension (300, 500));

      for (int i = 0; i < 5; i++)
      {
         JTextArea textArea;
         if (i % 2 == 0)
            textArea = new JTextArea ("1\n2\n3\n4\n5", 10, 20);
         else
            textArea = new JTextArea ("No scrolling needed", 2, 20);
         textArea.setPreferredSize (new Dimension (100, 50));
         JPanel titled = new JPanel (new BorderLayout());
         titled.add (new JScrollPane (textArea), BorderLayout.CENTER);
         titled.setBorder (new TitledBorder ("Panel: " + i));
         panel.add (titled);
      }

      JFrame frame = new JFrame ("Scroll Test");
      frame.setContentPane (new JScrollPane (panel));
      frame.pack();
      frame.show();
   }
}

---------- END SOURCE ----------
(Incident Review ID: 190070)
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