As i understood:
 - It's better not to use continuation, especially in multi threads.
 - There is a way to imitate it, like code sample below:

...
call MessageBox.new("Delete?"){|response|
  if response
    call MessageBox.new("Are you sure?"){|response2|
      delete if response2
    }
  end
}
...

Thanks for advices! :)
-- 
Posted via http://www.ruby-forum.com/.