directory picker failure

[Ludwin Janvier]

Steps:
1) in a empty directory, create 2 (or more) directories with the same prefix (e.g. '2014', '2015')
2) start a directory picker in any application that use it : nautilus, gthumb, ...
3) click on the 'Type a file name' button (the pen on the top left)
4) use the directory picker to select one of these directories ('2014')
5) you can't - there's still the prefix ('201')

screencast available here:
http://youtu.be/FxEMTHe_k1o

This bug won't happen if :
- there is a directory which doesn't share the same prefix
- you don't use the 'Type a file name' button. Once you have use it, it will be activated for every directory chooser you start.

standard 14.04.1 installation (unity), last updates