Name: skT88420 Date: 11/17/99


Sorry, my bug report wasn't very clear. The printout you see indicates the bug - the fact that dragGestureRecognized is called means that the system thinks that a drag is going on. To make it more apparent, here's a new version that goes ahead and starts the drag process, so you'll see the drag happen.]

Each JInternalFrame in this example contains a JLabel that is a drag source. If you click and release on a JLabel that is in an inactive JInternalFrame, a drag gets initiated, even though you haven't moved the mouse. The drag-cursor appears, and you have to hit Esc to get out of it.

What's happening is that the mouse-pressed is on the JInternalFrame's glass pane, which activates the pane, which causes the glass pane to be hidden. On the next mouse event (mouse-released or mouse-moved), this causes LightweightDispatcher to send the glass pane a mouse-exit event, which gets routed to the JLabel, which causes WMouseDragGestureRecognizer to recognize a drag gesture.

You can prevent this problem by installing your own glass pane, which ignores mouse-exit events (and therefore prevents them from getting sent to the JLabel) when the glass pane is hidden. However, after you do this, drag-and-drop is disabled for the inactive JInternalFrame. That is, you can't mouse-press on a component in an inactive window and drag it (like you can in Windows, for example). This is because the mouse-pressed, and therefore all the mouse-drags, go to the glass pane, instead of the drag source (the JLabel).

I believe that this is a *different* bug than the one described in 4218515.

import java.util.*;
import java.awt.*;
import java.awt.dnd.*;
import java.awt.datatransfer.*;
import javax.swing.*;

public class DesktopTest implements DragGestureListener, DragSourceListener
{
public final static void main (String[] args)
{
new DesktopTest();
}

DesktopTest()
{
JFrame f = new JFrame("hi");
f.setBounds(100,100,500,500);

JDesktopPane d = new JDesktopPane();
d.setBounds(0,0,500,500);
f.getContentPane().add(d);

createInternalFrame("one", 100, 100, d);
createInternalFrame("two", 250, 100, d);

f.setContentPane(d);
f.show();
}

private void createInternalFrame(String title, int x, int y, JDesktopPane d)
{
JInternalFrame i = new JInternalFrame();
i.setBounds(x,y,100,100);
i.setTitle(title);
d.add(i);

JLabel p = new JLabel("HI");
DragSource dragsource = new DragSource();
dragsource.createDefaultDragGestureRecognizer(p
, DnDConstants.ACTION_COPY_OR_MOVE
, this);
i.getContentPane().add(p);
i.show();
}

public void dragGestureRecognized(DragGestureEvent dge)
{
System.out.println("dragGestureRecognized");
Thread.dumpStack();
dge.startDrag(DragSource.DefaultMoveNoDrop
, new StringSelection("test")
, this);
}

public void dragDropEnd(DragSourceDropEvent dsde) {}
public void dragEnter(DragSourceDragEvent dsde) {}
public void dragExit(DragSourceEvent dse) {}
public void dragOver(DragSourceDragEvent dsde) {}
public void dropActionChanged(DragSourceDragEvent dsde) {}
}
(Review ID: 96907)
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