Sequencer time bar doesn't update when playing a sequence?

I have a simple level sequencer which fades a level in and out, and switches visibility of sub levels. The sequence works correctly, but the time bar doesn’t scroll when playing in editor. I’ve looked everywhere for a setting to turn this on, and have noted there is an autoscroll option in the editor preferences, but the autoscroll would only work if the time bar is moving, which it isn’t. It’s as if the sequence window isn’t “live”.

Note that I can scrub the time bar manually and will see the appropriate actions in the editor viewport.

Is this a simple check box I haven’t yet found?

I think I’m okay to bump this now, right?