While scrolling up and down the All-Contacts view, the app bar on the right (or left) will disappear and be replaced by a draggable scroller for quick scrolling.
Sometimes, the app bar doesn't pop right back, and then it looks like you can initiate any action with your contacts.
Drag any contact a bit, or scroll the view up an down (all it takes is a little wiggle) and the app bar pops back up.