iTunes synchronizes iPod even when turned off

Even though I switched on "prevent automatic synchronization of iPods..." in iTunes (translation, in German it's "Automatische Synchronisierung von iPods, ... verhindern"), iTunes won't stop synchronizing when I plug in my iPod touch. How can I really deactivate it?

I use iTunes 12.0.1.26 with an iPod touch 32 GB (4G) MD058FD/A with iOS 6.1.6 (the newest supported version).