Bug 12585 Packages view should not provide file and resource transfer if Java element below CU is selected
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
lt, 
			ResourceTransfer.getInstance(),
			FileTransfer.getInstance()};
		
		
		TransferDropTargetListener[] dropListeners= new TransferDropTargetListener[] {
			new SelectionTransferDropAdapter(fViewer),
			new FileTransferDropAdapter(fViewer)
		};
		fViewer.addDropSupport(ops, transfers, new DelegatingDropAdapter(dropListeners));
		
		
		Control control= fViewer.getControl();
		TransferDragSourceListener[] dragListeners= new TransferDragSourceListener[] {
			new SelectionTransferDragAdapter(fViewer),
			new ResourceTransferDragAdapter(fViewer),
			new FileTransferDragAdapter(fViewer)
		};
		DragSource source= new DragSource(control, ops);
		
		source.addDragListener(new DelegatingDragAdapter(dragListeners));
	}
	/**
	 * Handles double clicks in viewer.
	 * Opens editor if file double-clicked.
	 */
	private void handleDoubleClick(DoubleClickEvent event) {
		fActionSet.handleDoubleClick(event);
	}
	/**