volume not showing

Ever since the iOS 9 update, when I adjust the volume using the manual button on the bottom (or top depending on the orientation) of the iPad, the little volume display box no longer pops up on the screen. It's annoying because I can't tell if I'm adjusting the volume up or down (until the volume change is great enough). Every once in a while the display box will pop up like it used to do, but most of the time it is nowhere to be seen. Anyone else having this problem and how to fix?