Bug 32224 [Show In]Back-linking doesn't work for .class files in jars
Build 20030218 1. Enable back-linking in Package Explorer 2. Open Object (in rt.jar) Observe: An editor on Object.class opens (it shows the attached source). However Object.class is not shown in Package Explorer Note that Alt-Shift-s->Package Explorer doesn't work either.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/PackageExplorerPart.java
TransferDropTargetListener[] dropListeners= new TransferDropTargetListener[] {
			new SelectionTransferDropAdapter(fViewer),
			new FileTransferDropAdapter(fViewer)
		};
		fViewer.addDropSupport(ops | DND.DROP_DEFAULT, 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) {
			public void dragStart(DragSourceEvent event) {
				IStructuredSelection selection= (IStructuredSelection)getSelection();
				if (selection.isEmpty()) {
					event.doit= false;
					return; 
				}
				for (Iterator iter= selection.iterator(); iter.hasNext(); ) {
					if (iter.next() instanceof IMember) {
						setPossibleListeners(new TransferDragSourceListener[] {new SelectionTransferDragAdapter(fViewer)});
						break;
					}
				}
				super.dragStart(event);
			}