Description Scott Kovatch 2011-01-08 19:01:43 EST

+++ This bug was initially created as a clone of Bug #333375 +++

Using the following snippet, one can reproduce (by dragging the first tree item downwards to that the tree starts scrolling) that on Windows XP the client area's y coordinate remains unchanged during the scroll operation, while on MacOSX Cocoa, the y coordinate is indeed increased.

import org.eclipse.swt.SWT;
import org.eclipse.swt.dnd.DND;
import org.eclipse.swt.dnd.DragSource;
import org.eclipse.swt.dnd.DragSourceEvent;
import org.eclipse.swt.dnd.DragSourceListener;
import org.eclipse.swt.dnd.DropTarget;
import org.eclipse.swt.dnd.DropTargetEvent;
import org.eclipse.swt.dnd.DropTargetListener;
import org.eclipse.swt.dnd.TextTransfer;
import org.eclipse.swt.dnd.Transfer;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Tree;
import org.eclipse.swt.widgets.TreeItem;

public class Bug332956 {

	public static void main(String[] args) {
		Display display = new Display();
		Shell shell = new Shell(display);
		shell.setLayout(new FillLayout());
		final Tree tree = new Tree(shell, SWT.MULTI | SWT.H_SCROLL
				| SWT.V_SCROLL);
		for (int i = 0; i < 20; i++) {
			TreeItem iItem = new TreeItem(tree, 0);
			iItem.setText("TreeItem (0) -" + i);
			for (int j = 0; j < 4; j++) {
				TreeItem jItem = new TreeItem(iItem, 0);
				jItem.setText("TreeItem (1) -" + j);
				for (int k = 0; k < 4; k++) {
					TreeItem kItem = new TreeItem(jItem, 0);
					kItem.setText("TreeItem (2) -" + k);
					for (int l = 0; l < 4; l++) {
						TreeItem lItem = new TreeItem(kItem, 0);
						lItem.setText("TreeItem (3) -" + l);
					}
				}
			}
		}
		DragSource ds = new DragSource(tree, DND.DROP_COPY | DND.DROP_MOVE
				| DND.DROP_LINK);
		ds.setTransfer(new Transfer[] { TextTransfer.getInstance() });
		ds.addDragListener(new DragSourceListener() {

			public void dragStart(DragSourceEvent event) {
				// System.out.println("drag started " + event);
			}

			public void dragSetData(DragSourceEvent event) {
				// System.out.println("drag set data " + event);
				event.data = "Test";
			}

			public void dragFinished(DragSourceEvent event) {
				// System.out.println("drag finished " + event);
			}
		});

		DropTarget dt = new DropTarget(tree, DND.DROP_COPY | DND.DROP_MOVE
				| DND.DROP_LINK);
		dt.setTransfer(new Transfer[] { TextTransfer.getInstance() });
		dt.addDropListener(new DropTargetListener() {
			public void dragEnter(DropTargetEvent event) {
				// System.out.println("drag enter " + event);
			}

			public void dragLeave(DropTargetEvent event) {
				// System.out.println("drag leave " + event);
			}

			public void dragOperationChanged(DropTargetEvent event) {
				// System.out.println("drag operation changed " + event);
			}

			public void dragOver(DropTargetEvent event) {
				// System.out.println("drag over " + event);
				event.feedback = DND.FEEDBACK_SCROLL | DND.FEEDBACK_EXPAND;
				System.out.println("CLIENT AREA: " + tree.getClientArea());
			}

			public void drop(DropTargetEvent event) {
				// System.out.println("drop " + event);
			}

			public void dropAccept(DropTargetEvent event) {
				// System.out.println("drop accept " + event);
			}
		});

		shell.setSize(200, 200);
		shell.open();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch())
				display.sleep();
		}
		display.dispose();
	}
}

I assume that the behavior on other platforms is the same as on Windows XP, because GEF bug #332956, which is indirectly caused by this misbehavior on MacOSX Cocoa, does not seem to occur on any other platforms.