every 2nd Tab on f? alternates between docs-only and source for function f (with docs) defined in a cell

What steps will reproduce the problem?
1. create an input cell like this:
def f():
   """
   Whatever
   """
   return 1
2. in the next cell, type f? and hit Tab. Keep hitting Tab, once every few 
seconds.

What is the expected output? 

Documentation for f (i.e. "Whatever" string), but no source.

What do you see instead?

Alternatively, documentation for f, and source code for f. 

What version of the product are you using? On what operating system?

both "classic" and flask-based nb, with Sage 4.7.1.

Please provide any additional information below.

Same with f?? (alternating between source and documentation views)

Original issue reported on code.google.com by dimp...@gmail.com on 29 Aug 2011 at 12:46

Letractively / sagenb

every 2nd Tab on f? alternates between docs-only and source for function f (with docs) defined in a cell #47