Description Alexander Zakusylo 2019-06-26 04:59:01 EDT

Create an SWT control and implement a DragSource for it (using SWT API), 
then create an embedded AWT frame and implement a DropTarget for AWT component (using AWT API).
 Drag and drop from SWT to AWT does not work: the AWT DropTarget does not receive any events.

It's a regression: SWT 4.6 and 4.6.3 work fine, versions 4.7-4.12 are broken.

Snippet to reproduce is below.
Run the app and DND the 1st button onto the 3rd one

public static void main(String[] args) {

  Shell shell = new Shell(SWT.DIALOG_TRIM);
  shell.setLayout(new GridLayout(3, true));

  Button sourceButton = new Button(shell, SWT.PUSH);
  sourceButton.setText("Source");

  Button targetButton = new Button(shell, SWT.PUSH);
  targetButton.setText("SWT Target");

  Composite swingContainer = new Composite(shell, SWT.EMBEDDED);
  Frame frame = SWT_AWT.new_Frame(swingContainer);

  JButton swingButton = new JButton("Swing target");
  frame.add(swingButton);

  shell.open();
  shell.pack();

  DragSource ds = new DragSource(sourceButton, DND.DROP_MOVE);
  ds.setTransfer(new Transfer[] { TextTransfer.getInstance() });
  ds.addDragListener(new DragSourceAdapter() {
    @Override
    public void dragSetData(DragSourceEvent event) {
      event.data = "Hello";
    }
  });

  DropTarget dt = new DropTarget(targetButton, DND.DROP_MOVE);
  dt.setTransfer(new Transfer[] { TextTransfer.getInstance() });
  dt.addDropListener(new DropTargetAdapter() {
    @Override
    public void drop(DropTargetEvent event) {
      System.err.println("Drop success: " + event.data);
    }
  });

  java.awt.dnd.DropTarget awtdt = new java.awt.dnd.DropTarget(swingButton, new DropTargetListener() {

    @Override
    public void dropActionChanged(DropTargetDragEvent dtde) {
    }

    @Override
    public void drop(DropTargetDropEvent dtde) {
      dtde.acceptDrop(DnDConstants.ACTION_MOVE);
      System.err.println("drop " + dtde.getTransferable());
    }

    @Override
    public void dragOver(DropTargetDragEvent dtde) {
      System.err.println("Drap over");

    }

    @Override
    public void dragExit(java.awt.dnd.DropTargetEvent dte) {

    }

    @Override
    public void dragEnter(DropTargetDragEvent dtde) {
      System.err.println("Drag enter");
    }
  });

  Display display = shell.getDisplay();
  while (!shell.isDisposed()) {
    if (!display.readAndDispatch()) {
      display.sleep();
    }
  }
}