Hi, everyone I'm new to Macbook and today I'm having a problem receiving notifications. At first I was text messaging my friends on my iphone and I noticed that my macbook wasn't alerting me with any message like it usually does. So I opened Notifications in the System Preferences and I found that all the apps just disappeared from the sidebar that contains all the apps that have notification option. The only app still there in the "Do not Disturb''. Can someone help me restoring my configuration, I don't want to reinstall everything and set it back the way it was, I have a lot of applications. Thank you.