emails

I used to be able to send an email or forward an email by clicking on "forward" and my address book would show up at the left side of the screen and I could click on the names I wanted to send or forward the note and it would add them to the "send to" of my email so I could send it to multiple people. For some reason that has now stopped and I can only send to one person at a time which is very cumbersome and time consuming. Does anyone know how to solve this problem? I hope I'm describing it right.