Annoying thing in Premiere Elements 15

On the timeline, whenever I press "PLAY", either by clicking the Play/Pause toggle button, or by hitting the space bar, a pretty big black box pops up over the Render button that says, "Render:  For smooth, high quality playback, render your timeline".  The box will also pop up if I hover the mouse over the Render button.  It will stay up for 3 or 4 seconds, and will not go away by clicking it.

It's irritating.  How do I switch it off?  Thanks!