PowerPoint task pane tabs

I few days ago I was working in PowerPoint and I opened the Animation Pane. Later I opened the Selection Pane and the Animation Pane collapsed into a small icon forming a tab down the right-hand side of the screen. I then was able to open the Format Background Pane and then I had two icons forming tabs on the right of the screen, the Animation and Selection panes. Simply selecting any of the icons brought the specific pane forward while the other panes collapsed to the icon tab.

The following day I opened PowerPoint and I can no longer get the task panes to collapse to this icon tab bar. 

Does anyone know why this feature would come and go or how I can get this truly functional feature to operate? This saves time having to hunt down the various task panes when you need them and keeps them handy rather than have multiple panes open and hogging all the screen space.