harmonic cursor should be visible when "follow playback" off

The harmonic cursor, and other descriptive elements, are shown on the panes when playback is stopped and are not shown (to avoid confusion and excess work during scrolling) when playback is running.

However, if the user explicitly stops the panes scrolling during playback by setting Follow Playback to off, these artifacts should be displayed again -- the panes should behave as if playback is not happening.