Folders automatically added to favorites (unwanted)

I'm having this issue when opening my session that I use for when scanning with my tethered camera, that my dropbox folder automatically is added to favorites. I sometimes develop files to this folder, but it's not set as output folder. So every time I open my session I have to add the dropboxfolder to favorites and then remove it from favorites, then all is good. I'm just wondering why this behaviour is? Can anyone help me?