

The grey lightning bolt ones you can technically delete. If you click on one it will show you which has priority. If you want to change which has priority, just move them up or down. Simply put, the symbol for the lightning bolt with the green plus means that you have given that file priority over another (one with a red symbol). If you followed the tutorial, it should tell you more or less how to do it. I also know a little German (very little) I hope what I say isn't too hard for you to understand.
