Category / sub category “view all” display

Question

I have just been testing CE 1.9 using the rwd theme.

I have set up a simple category tree as follows"

Default Category
- Cat 1
--- Sub cat 1
--- Sub cat 2
--- Sub cat 3
--- Sub cat 4
- Cat 2
- Cat 3

On the front end main Navigation I'm getting an additional "View All Cat 1" link as follows:

Cat 1
- View all Cat 1
- Sub cat 1
- Sub cat 2
- Sub cat 3
- Sub cat 4

Where is the "view all" link coming form (it simply redirects to Cat1)?

Thanks.