Bug 257855 [CommonNavigator] Supporting Custom Transfertypes in Common Navigator Framework
bundles/org.eclipse.ui.navigator/src/org/eclipse/ui/navigator/CommonViewer.java
* 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 | DND.DROP_LINK;
		CommonDragAdapter dragAdapter = new CommonDragAdapter(contentService,
				this);
		addDragSupport(operations, dragAdapter.getSupportedDragTransfers(),
				dragAdapter);
		
		CommonDropAdapter dropAdapter = new CommonDropAdapter(contentService,
				this);
		addDropSupport(operations, dropAdapter.getSupportedDropTransfers(),
				dropAdapter);
		NavigatorDnDService dnd = (NavigatorDnDService)contentService.getDnDService();
		dnd.setDropAdaptor(dropAdapter);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.AbstractTreeViewer#createTreeItem(org.eclipse.swt.widgets.Widget,
	 *      java.lang.Object, int)
	 */