under win32, calling requestFocus() with the mouse button down seems to leave the mouse button down until the next mouseclick in that same panel.
>From: ###@###.### (Doug Stein)
To: java@java
Subject: Bug report: Erroneous mouse events with AWT on Windows


Platform: Window95 and WindowsNT (not Solaris/Motif)
JDK version: JDK-1_0-win32-x86.exe
Priority: Medium (Low/Medium/High/Critical)

Synopsis
--------

AWT mouse events become scrambled if requestFocus() is called
while the mouse is down.


Description and reproducible test case
--------------------------------------

This bug only occurs on Window95 and WindowsNT, and does not
happen with Motif.

Calling requestFocus() while the mouse is down scrambles subsequent
mouse events. The following test case demonstrates the problem.
Removing the requestFocus() call from the code eliminates the bug.

- Compile and run mousedrag.java:

javac mousedrag.java
java mousedrag

- Perform a drag operation from the blue area on the left to the blue
  area on the right (mouseDown in left, drag, mouseUp in right).
  Notice the corrent stream of mouse events:

    mouseDown x y
    mouseDrag x y
    ...
    mouseUp x y

- Now perform a drag operation from the red area to the blue area. An
  erroneous stream of mouse events is generated. The (x,y) coordinates
  for many of these events are incorrect. It generates something like
  this:

    mouseDown
    mouseDrag
    mouseUp
    mouseDown
    mouseDrag
    mouseDrag
    ...
    (sometimes a mouseDown event gets injected somewhere in here if you
     drag across the textfield)
    ...
    mouseUp

- Now move the mouse around over the red area (don't press the mouse
  button). You will get a bunch of erroneous mouseDrag events. The
  red panel seems to think that the mouse is still pressed.


Workaround
----------

Don't call getFocus() while the mouse is pressed.


------------------------------------------------------------------------


I will be reporting quite a few additional AWT bugs. Please let me
know if this format for bug reporting is acceptable. I am planning to
include reproducible test cases with all the bugs. I haven't yet
mailed in all the bugs I have discovered because writing good test
cases takes time.

It would be helpful to know when/if bugs will be fixed. If you could
send me some email when evaluating these bugs it would be very
helpful.


Thanks,

- Doug

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import java.awt.*;

class smallpanel extends Panel {
  public Dimension minimumSize() {
    return new Dimension(80, 80);
  }
  public Dimension preferredSize() {
    return minimumSize();
  }
}

public class mousedrag extends Frame {
  public static void main(String argv[]) {
    new mousedrag();
  }

  private TextField textfield;
  private Panel topPanel, leftPanel, rightPanel;
  
  public mousedrag() {
    textfield = new TextField("TextField");
    topPanel = new smallpanel();
    topPanel.setBackground(Color.red);
    leftPanel = new smallpanel();
    leftPanel.setBackground(Color.blue);
    rightPanel = new smallpanel();
    rightPanel.setBackground(Color.blue);
    
    add("Center", textfield);
    add("North", topPanel);
    add("West", leftPanel);
    add("East", rightPanel);
    
    show();
    resize(preferredSize());
    validate();
  }

  public boolean mouseDown(Event e, int x, int y) {
    if (e.target == topPanel)
      textfield.requestFocus();
    System.out.println("mouseDown " + x + " " + y);
    return true;
  }
  
  public boolean mouseUp(Event e, int x, int y) {
    System.out.println("mouseUp " + x + " " + y);
    return true;
  }
  
  public boolean mouseDrag(Event e, int x, int y) {
    System.out.println("mouseDrag " + x + " " + y);
    return true;
  }
}