Bug 30655 [DND] Check selection in NavigatorDragAdapter.dragStart
bundles/org.eclipse.ui.views/src/org/eclipse/ui/views/navigator/NavigatorDragAdapter.java
ISelectionProvider selectionProvider;
	private static final String CHECK_MOVE_TITLE = ResourceNavigatorMessages.getString("DragAdapter.title"); 
	private static final String CHECK_MOVE_MESSAGE = ResourceNavigatorMessages.getString("DragAdapter.checkMoveMessage"); 
	private static final String CHECK_DELETE_MESSAGE = ResourceNavigatorMessages.getString("DragAdapter.checkDeleteMessage"); 	
	/**
	 * Constructs a new drag adapter.
	 */
	public NavigatorDragAdapter(ISelectionProvider provider) {
		selectionProvider = provider;
	}
	/**
	 * @see DragSourceListener#dragFinished
	 */
	public void dragFinished(DragSourceEvent event) {
		LocalSelectionTransfer.getInstance().setSelection(null);
		if (event.doit == false) {
			return;
		}
		final int typeMask = IResource.FOLDER | IResource.FILE;
		if (event.detail == DND.DROP_MOVE) {
			IResource[] resources = getSelectedResources(typeMask);	
			DragSource dragSource = (DragSource) event.widget;
			Control control = dragSource.getControl();
			Shell shell = control.getShell();
			ReadOnlyStateChecker checker;
			
			if (resources == null || resources.length == 0)