Bug 5699 Add ResourceTransfer to packages view
The packages view should add the ResoruceTransfer as a drag source to its list of transfers
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/packageview/SelectionTransferDropAdapter.java
Assert.isTrue(false); 
					return false;
			}
		}
		
		private static int askIfUpdateReferences(){
			Shell shell= JavaPlugin.getActiveWorkbenchShell().getShell();
			String title= "Move";
			String preview= "Pre&view";
			String question= "Do you want to update references to the moved element(s)? Press '" + preview + "' to see the preview of the reference updates.";
			
			String[] labels= new String[] {IDialogConstants.YES_LABEL, IDialogConstants.NO_LABEL,
																 preview,  IDialogConstants.CANCEL_LABEL };
			final MessageDialog dialog = new MessageDialog(shell, title, null, question, MessageDialog.QUESTION,	labels, 2); 
			shell.getDisplay().syncExec(new Runnable() {
				public void run() {
					dialog.open();
				}
			});
			int result = dialog.getReturnCode();
			if (result == 0)
				return IDialogConstants.YES_ID;
			if (result == 1)
				return IDialogConstants.NO_ID;
			if (result == 2)
				return PREVIEW_ID;
			return IDialogConstants.CANCEL_ID;
		}
	}
}