automatic classes in menu structure

[Connie]

I just stumbled upon a situation, which astonished me:

I am building a complete new testinstallation of GS 3 and try to note all plugins which I use.
So i created a page

"p01-contact"

And what did I notice in my sidemenue?

http://www.urbanistan.de/getsimple/index...ch-benutze

this list-item had yellow background. The reason?

I assume that per default classes are added to the items: so in this case this classes:

Code:

<li class="p01-contact plugins-die-ich-benutze">

and as I had defined a class for the p01-plugin, this class was added automatically ..

Where can I change this behaviour and what is the reason for this behaviour? Is it standard or from a plugin? (all my plugins are listed at that page...)