Bug 135971 [CommonNavigator] Project Explorer: cannot drop to Hierarchy view
You can drag and drop an element onto the Hierarchy view from the Outline or Package Explorer. You cannot from the Project Explorer, you get a drop disabled cursor.
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonViewer.java
* @since 3.4
	 */
	public CommonNavigator getCommonNavigator() {
		return commonNavigator;
	}
	
	protected void removeWithoutRefresh(Object[] elements) {
		super.remove(elements);
	}
	/**
	 * <p>
	 * Adds DND support to the Navigator. Uses hooks into the extensible
	 * framework for DND.
	 * </p>
	 * <p>
	 * By default, the following Transfer types are supported:
	 * <ul>
	 * <li>LocalSelectionTransfer.getInstance(),
	 * <li>PluginTransfer.getInstance()
	 * </ul>
	 * </p>
	 * 
	 * @see CommonDragAdapter
	 * @see CommonDropAdapter
	 */
	protected void initDragAndDrop() {
		
		int operations = DND.DROP_COPY | DND.DROP_MOVE;
		CommonDragAdapter dragAdapter = new CommonDragAdapter(contentService,
				this);