iPhone vibrates in spite of "Do Not Disturb"

When i switch my iPhone 5 (iOS 7) to "Do Not Disturb"-Mode, and also activate "Always" in the Silence-Settings, it vibrates when it is unlocked. > So when i am reading an iMessage, and it arrives a new one, my iPhone > vibrates. **I want to switch my iPhone completely silent with this option**, but it is really possible? I can turn off vibration, of course, but i really don't know what Do Not Disturb really does! It turns of Vibration and Sound when new Notifications arriving, but when i am using the Phone, it should be complete silent as well. > Is this a bug or just a missing feature?