Timeline doesn't scroll with playhead


Linux, Ubuntu 16.04.4, v=18.07

20 min time line, Zoom to 50%, (12 seconds fit on my screen/window.)
hit Play, watch playhead marker move across the timeline as the video plays.
When it gets to the right side of the screen, it disappears, the timeline does not scroll like I expect.

Also, if I pause and click “Skip to the next point (Alt-Right)” the timeline doesn’t move so I can see the point. (the playhead does)


restarted Shotcut, now it scrolls.