Bug 126658 [CommonNavigator] [DND] Complete definition of DND API
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonDragAdapter.java
private final INavigatorContentService contentService;
	private final ISelectionProvider provider;
	/**
	 * Create a DragAdapter that drives the configuration of the drag data.
	 * 
	 * @param aContentService
	 *            The content service this Drag Adapter is associated with
	 * @param aProvider
	 *            The provider that can give the current selection from the
	 *            appropriate viewer.
	 */
	public CommonDragAdapter(INavigatorContentService aContentService,
			ISelectionProvider aProvider) {
		super();
		contentService = aContentService;
		provider = aProvider;
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.swt.dnd.DragSourceAdapter#dragStart(org.eclipse.swt.dnd.DragSourceEvent)
	 */
	public void dragStart(DragSourceEvent event) {
		try {
			
			DragSource dragSource = (DragSource) event.widget;
			Control control = dragSource.getControl();
			if (control != control.getDisplay().getFocusControl()) {