[SWT] FXCanvas doesn't deliver drag exited events after successful drop

DropTargetListener in FXCanvas$HostContainer class uses an "ignoreleave" flag to prevent drag leave after drop resulting in a javafx drag exited event. but this flag is never reset.

i cannot attach a file so i'm pasting the test case code and fix.

==== TestCase.java ====

import javafx.embed.swt.FXCanvas;
import javafx.event.EventHandler;
import javafx.event.EventType;
import javafx.scene.Scene;
import javafx.scene.control.TextArea;
import javafx.scene.input.DragEvent;
import javafx.scene.input.Dragboard;
import javafx.scene.input.TransferMode;
import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceAdapter;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;

/**
 * Demonstrates that {@link javafx.embed.swt.FXCanvas} does not deliver any
 * {@link javafx.scene.input.DragEvent#DRAG_EXITED} and
 * {@link javafx.scene.input.DragEvent#DRAG_EXITED_TARGET} after a successful
 * drop.
 * <p>
 * Steps to reproduce:
 * </p>
 * <ol>
 * <li>Start dragging from the left SWT label.</li>
 * <li>Drop into the JavaFX text area.</li>
 * <li>Start dragging from the left SWT label once more.</li>
 * <li>Drag over the JavaFX text area.</li>
 * <li>Drop into the right SWT label.</li>
 * </ol>
 */
public class TestCase {

  public static void main( String[] args ) {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setText("JavaFX/SWT DnD Interoperability");
    shell.setLayout(new GridLayout(3, false));


    final Label label1 = new Label(shell, SWT.CENTER | SWT.BORDER);
    label1.setText("Step 1: Drag from here.\nStep 3: Drag from here.");
    label1.setLayoutData(new GridData(GridData.FILL_BOTH));
    final Transfer[] transfers = new Transfer[]{TextTransfer.getInstance()};
    final DragSource dragSource = new DragSource(label1, DND.DROP_COPY);
    dragSource.setTransfer(transfers);
    dragSource.addDragListener(new DragSourceAdapter() {
      @Override
      public void dragSetData( final DragSourceEvent event ) {
        event.data = "Step 4: Drag text over text area.";
      }
    });


    final FXCanvas fxCanvas = new FXCanvas(shell, SWT.NONE);
    final TextArea textArea = new TextArea();
    textArea.setText("Step 2: Drop text here.");
    textArea.addEventFilter(DragEvent.ANY, new EventHandler<DragEvent>() {
      @Override
      public void handle( final DragEvent event ) {
        event.acceptTransferModes(TransferMode.COPY);

        final EventType<DragEvent> type = event.getEventType();
        if (type != DragEvent.DRAG_OVER) {
          System.out.println(type);
        }

        if (type == DragEvent.DRAG_DROPPED) {
          final Dragboard db = event.getDragboard();
          if (db != null) {
            if (db.hasString()) {
              textArea.setText(db.getString());
            }
          }
          event.setDropCompleted(true);
        }

        event.consume();
      }
    });
    final Scene scene = new Scene(textArea);
    fxCanvas.setScene(scene);
    fxCanvas.setLayoutData(new GridData(GridData.FILL_BOTH));


    final Label label2 = new Label(shell, SWT.CENTER | SWT.BORDER);
    label2.setText(
            "Step 5: Drop text here.\n" +
            "(Will have not visible effect.)");
    label2.setLayoutData(new GridData(GridData.FILL_BOTH));


    shell.open();

    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}



=== FIX FXCanvas.java ====
== method in anonymous listener in createDropTarget of HostContainer ==

public void dragEnter(DropTargetEvent event) {

  ignoreLeave = false; // this is the fix

  dropTarget.setTransfer(getAllTransfers());
  detail = event.detail;
  operations = event.operations;
  dragOver (event, true, detail);
}