Created attachment 521805 [details]
~/.xsession-errors

Description of problem:

This happens very often:

After the todays morning updates (sep 07)  having a heavy problem with gnome-shell-sessions:

Each time I traverse the Activities button (screen top left), my gnome
session dies with "Oh no, something has gone wrong...". I can reproduce this!
It seems it has nothing to do with installed gnome-shell-extensions, because if I remove all extensions, I have still this behaviour.

Creating a new user, this user shows the "Avctivities" drop down menu
properly and starts the app if clicking on it's icon.

But if I change for this new user the window theme by gnome-tweak-tool
from default to Clearlooks (for example), then the gnome session crashes mostly 
too for this new user. By resetting the window theme I get rid from this
bug.

It seems something in my homedirectory is the culprit for this, but what?

Version-Release number of selected component (if applicable):
gnome-shell-3.1.4-2.gite7b9933.fc16.x86_64

How reproducible:
Very often, but not always

Steps to Reproduce:
1.Login into a gnome session
2.Touch the Activities button
3.
  
Actual results:
The session dies with "Oh no. Something has gone wrong"

Expected results:
The session continues

Additional info:

1. I saw some errors in ~/.xsession-errors. I'll attach it
2. There seems to be a weird "self-healing" effect, because after some time (login, crash, login again, multiple times) I can click the Activities button and show the correspondent menu (the session continues)