Description of problem:
Gnome shell refuses to start when gtk3  is installed.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. install gtk3
2. try to start gnome-shell
When loading gdk-pixbuf-loader it complains that it cannot load version 2.0, because version 3.0 is already loaded (if you need the exact error I can reproduce it later).
Should start without issues.
After removing gtk3, it starts.
*** Bug 592535 has been marked as a duplicate of this bug. ***
*** Bug 592536 has been marked as a duplicate of this bug. ***
Obviously fine with GTK+-3.0 based GNOME Shell in Fedora 15.