FULL PRODUCT VERSION :
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Darwin 15.6.0 Darwin Kernel Version 15.6.0: Sun Jun 4 21:43:07 PDT 2017; root:xnu-3248.70.3~1/RELEASE_X86_64 x86_64

A DESCRIPTION OF THE PROBLEM :
Dragging a component - as per the test program - does not work in subdialogs (It does work in a window component).



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
See Test-Porgram

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Dragging works
ACTUAL -
Dragging does not work

REPRODUCIBILITY :
This bug can be reproduced always.

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import java.awt.BorderLayout;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.awt.dnd.DnDConstants;
import java.awt.dnd.DragGestureEvent;
import java.awt.dnd.DragGestureListener;
import java.awt.dnd.DragSource;
import java.awt.dnd.DragSourceAdapter;
import java.awt.dnd.DragSourceDragEvent;
import java.awt.dnd.DragSourceEvent;
import java.awt.dnd.DragSourceListener;
import java.awt.dnd.DropTargetAdapter;
import java.awt.dnd.DropTargetDropEvent;
import java.awt.event.ActionEvent;
import java.io.IOException;

import javax.swing.AbstractAction;
import javax.swing.Action;
import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JTextArea;

public class Drag {

    private static JTextArea console = new JTextArea();

    static public void main(String[] s) {
        JFrame f = new JFrame();
        f.setSize(800, 600);
        f.getContentPane().setLayout(new BorderLayout());
        f.getContentPane().add(new JButton(openDialog(f)), BorderLayout.NORTH);
        f.getContentPane().add(console, BorderLayout.CENTER);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private static Action openDialog(JFrame f) {
        return new AbstractAction("open Drag'n'Drop Dialog"){
            public void actionPerformed(ActionEvent e) {
                JDialog dialog = new JDialog(f);
                dialog.getContentPane().setLayout(new BorderLayout());
                JList<String> list = new JList<String>(new String[]{"drag me ->"});
DragSource.getDefaultDragSource().createDefaultDragGestureRecognizer(list, DnDConstants.ACTION_COPY_OR_MOVE, new DragGesture());

                JLabel lbl = new JLabel("drop here");
                lbl.setDropTarget(new DropTarget(lbl));
                dialog.getContentPane().add(list, BorderLayout.WEST);
                dialog.getContentPane().add(lbl, BorderLayout.CENTER);
                dialog.setSize(300, 180);
                dialog.setLocationRelativeTo(f);
                dialog.setVisible(true);
            }

        };
    }

    static class DragGesture implements DragGestureListener {
        public void dragGestureRecognized(DragGestureEvent dge) {
            console.setText(console.getText() + "\ndragGesture: \t" + dge.toString());
            Transferable transferable =new Transferable() {
                public boolean isDataFlavorSupported(DataFlavor flavor) {
                    return true;
                }
                public DataFlavor[] getTransferDataFlavors() {
                    return new DataFlavor[]{DataFlavor.stringFlavor};
                }
                public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
                    return "transferData";
                }
            };
            DragSourceListener sourceListener = new DragSourceAdapter() {
                public void dragExit(DragSourceEvent dse) {
                    console.setText(console.getText() + "\ndragExit: \t" + dse.toString());
                }
                public void dragEnter(DragSourceDragEvent dsde) {
                    console.setText(console.getText() + "\ndragEnter: \t" + dsde.toString());
                }
            };
            dge.startDrag(DragSource.DefaultCopyDrop, transferable, sourceListener);
        }
    }

    static class DropTarget extends java.awt.dnd.DropTarget {
        public DropTarget(JLabel lbl) {
            super(lbl, new DropTargetAdapter() {
                public void drop(DropTargetDropEvent dtde) {
                    try {
lbl.setText(dtde.getTransferable().getTransferData(DataFlavor.stringFlavor).toString());
                    } catch (Exception e) {
                        console.setText(e.getMessage());
                    }
dtde.acceptDrop(DnDConstants.ACTION_COPY_OR_MOVE);
                }
            });
        }
    }

}

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