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The osx x86_64 swt jar as available in the Eclipse 4.6 (Neon) release for OSX. It is suitable for use with jface and other dependencies available from maven central in the org.eclipse.scout.sdk.deps group. The sources is copied from swt-4.6-cocoa-macosx-x86_64.zip from http://download.eclipse.org/eclipse/downloads/drops4/R-4.6-201606061100/ and javadoc is generated from sources.

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/*******************************************************************************
 * Copyright (c) 2000, 2011 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.dnd;

import org.eclipse.swt.internal.cocoa.*;
import org.eclipse.swt.widgets.*;

/**
 * This class provides a default drag under effect (eg. select, insert, scroll and expand)
 * when a drag occurs over a Tree.
 *
 * Classes that wish to provide their own drag under effect for a Tree
 * can extend the TreeDropTargetEffect class and override any applicable methods
 * in TreeDropTargetEffect to display their own drag under effect.
 *
 * Subclasses that override any methods of this class must call the corresponding
 * super method to get the default drag under effect implementation.
 *
 * The feedback value is either one of the FEEDBACK constants defined in
 * class DND which is applicable to instances of this class,
 * or it must be built by bitwise OR'ing together
 * (that is, using the int "|" operator) two or more
 * of those DND effect constants.
 * 
 * 
 * 

 * Feedback:
 * FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL
 * 
 * 

 * Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or
 * FEEDBACK_INSERT_AFTER may be specified.
 * 
 *
 * @see DropTargetAdapter
 * @see DropTargetEvent
 * @see Sample code and further information
 *
 * @since 3.3
 */
public class TreeDropTargetEffect extends DropTargetEffect {
	boolean shouldEnableScrolling;

	/**
	 * Creates a new TreeDropTargetEffect to handle the drag under effect on the specified
	 * Tree.
	 *
	 * @param tree the Tree over which the user positions the cursor to drop the data
	 */
	public TreeDropTargetEffect(Tree tree) {
		super(tree);
	}

	int checkEffect(int effect) {
		// Some effects are mutually exclusive.  Make sure that only one of the mutually exclusive effects has been specified.
		if ((effect & DND.FEEDBACK_SELECT) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
		if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
		return effect;
	}

	/**
	 * This implementation of dragEnter provides a default drag under effect
	 * for the feedback specified in event.feedback.
	 *
	 * For additional information see DropTargetAdapter.dragEnter.
	 *
	 * Subclasses that override this method should call super.dragEnter(event)
	 * to get the default drag under effect implementation.
	 *
	 * @param event  the information associated with the drag enter event
	 *
	 * @see DropTargetAdapter
	 * @see DropTargetEvent
	 */
	@Override
	public void dragEnter(DropTargetEvent event) {
	}

	/**
	 * This implementation of dragLeave provides a default drag under effect
	 * for the feedback specified in event.feedback.
	 *
	 * For additional information see DropTargetAdapter.dragLeave.
	 *
	 * Subclasses that override this method should call super.dragLeave(event)
	 * to get the default drag under effect implementation.
	 *
	 * @param event  the information associated with the drag leave event
	 *
	 * @see DropTargetAdapter
	 * @see DropTargetEvent
	 */
	@Override
	public void dragLeave(DropTargetEvent event) {
		OS.objc_msgSend(control.view.id, OS.sel_setShouldExpandItem_, 1);
		if (shouldEnableScrolling) {
			shouldEnableScrolling = false;
			OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 1);
			control.redraw();
		}
	}

	/**
	 * This implementation of dragOver provides a default drag under effect
	 * for the feedback specified in event.feedback.
	 *
	 * For additional information see DropTargetAdapter.dragOver.
	 *
	 * Subclasses that override this method should call super.dragOver(event)
	 * to get the default drag under effect implementation.
	 *
	 * @param event  the information associated with the drag over event
	 *
	 * @see DropTargetAdapter
	 * @see DropTargetEvent
	 * @see DND#FEEDBACK_SELECT
	 * @see DND#FEEDBACK_INSERT_BEFORE
	 * @see DND#FEEDBACK_INSERT_AFTER
	 * @see DND#FEEDBACK_SCROLL
	 */
	@Override
	public void dragOver(DropTargetEvent event) {
		int effect = checkEffect(event.feedback);
		((DropTarget)event.widget).feedback = effect;
		OS.objc_msgSend(control.view.id, OS.sel_setShouldExpandItem_, (effect & DND.FEEDBACK_EXPAND) == 0 ? 0 : 1);
		if ((effect & DND.FEEDBACK_SCROLL) == 0) {
			shouldEnableScrolling = true;
			OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 0);
		} else {
			OS.objc_msgSend(control.view.id, OS.sel_setShouldScrollClipView_, 1);
		}
	}
}