Labeling in ClearCase views

We use TeamCity V3.0.1 with the new ClearCase labeling feature.
We have
- one shared VCS root: /viewstore/buildview/vobs/mc4li_mcdev/mcng
- build runner: Maven2
- 2 build configurations:
-- core: checkout rule: +:core
-- gui: checkout rule: +:gui
We turned on VCS labeling: enabled for successful builds only
and thought that
- core would label sub directory core upon successful build
- gui would label sub directory gui upon success.
However, both build configurations label the whole tree below VCS root.
Is this the intended behavior?

What do I have to do to get the behavior I have described above?