Outputs from long-running cell won't be shown without keeping browser tab open

[chenaren]

IPython version: 2.0.0
Steps to reproduce:

1. Create a notebook

2. Create a cell containing

    import time
    time.sleep(5)
    print 'Hello'

3. Run the cell and then immediately save the notebook and close the browser tab

4. Wait for 5 seconds to pass while the kernel is running

5. Open the notebook again and the assumed output 'Hello' wouldn't be there

Is it a bug or just the way IPython notebook supposed to work? If the latter is the case, I wonder what the most seamless workaround is. Thanks.