Color styles

I am using CorelDRAW X6 and being the amazing software it is, it's a pleasure to work on it. I have a small problem that is annoying (and time consuming too).

Color styles seem to build up regardless of any document i create. I mostly do not create any custom color palette but the color styles start building up automatically and it takes ages to get rid of them.

My questions are: 1. How to prevent Color styles from building up automatically.

2. How do Color styles work?