You understood me correctly, the toolbox/panels were open. Dorico moved the page after the green line reached the end of what would have been visible had the toolbox/panel been closed (or if you could see through the toolbox/panels).
Once again, this has happened so few times since October, that I chalked it up to something else happening. I haven’t seen the behavior in quite a few weeks, so I could be throwing something into the fire that doesn’t help the diagnosis of this problem.
Robby
I appreciate your frustration, Mark. As Daniel has mentioned many times before, we do have to take some difficult decisions about where to focus our time, and we do try to ensure that the widest range of customers get the best bang for their buck. Having said that, we do also spend considerable time looking at problems such as this that do only affect a handful of users. We do have some instrumentation code in Dorico already, but it currently doesn’t contain enough specific information to diagnose this particular problem. I do hope to spend some time adding a bit more instrumentation that could help.
One extra bit of information that could be relevant: does this happen in page view as well as galley view?
I know you do, Paul; and I feel bad (and I know I’m trying everyone’s patience) every time I mention it.
Of course. And you’re doing - if I may say - a magnificent job… look at the time now: way after hours for you. I (like everyone else) am truly grateful.
As Daniel has mentioned many times before, we do have to take some difficult decisions about where to focus our time, and we do try to ensure that the widest range of customers get the best bang for their buck. Having said that, we do also spend considerable time looking at problems such as this that do only affect a handful of users.
Understood. Thanks! And if you need a tester… 
We do have some instrumentation code in Dorico already, but it currently doesn’t contain enough specific information to diagnose this particular problem. I do hope to spend some time adding a bit more instrumentation that could help.
I’ll work the rest of today in Page view and see. (I usually work almost exclusively in Gallery.)
One extra bit of information that could be relevant: does this happen in page view as well as galley view?
Thanks very much again, Paul - and the Team!
Hi Paul,
It happens for me in both views.
And Robby I had the same thought so I waited and waited but the screen didn’t refresh no matter if the tool window was reached to its „invisible“ end.
If you try dragging the score around with the mouse does that cause it to ‘wake up’ and start updating again?
Paul,
You bring up an interesting point: hasn’t that functionality been removed from Dorico Pro 2?
I instinctively tried to do that on the morning I installed the upgrade - for reasons of plain positioning - and got a thick grey marquee instead. Have I inadvertently unset something?
Not to derail a thread so dear to my heart, though, dragging didn’t use to fix it in v.1.
Annoyingly - or pleasantly depending on attitude - I worked for four hours yesterday in Page View with not one instance of the phenomenon. I switched to Galley: nothing.
I do appreciate how tough this must be for you to troubleshoot - even to observe - and am grateful
By default hold down shift to drag it and with no modifier to make a marquis selection, but I think there’s also a preference to switch this behaviour.
Thanks, Paul!
Yes, I found the preference but - interestingly - it makes no difference, in case that’s helpful; I’m happy to use SHIFT+
Yes, Paul - it seems to .
Was working for three or four hours this afternoon without a relaunch; Galley View; up it cropped.
Two things that nay help:
Hope this may add something… somehow. Thanks!
Update: tried to ‘wake’ the scrolling today as you suggested - after the usual three to four hours, at which the phenomenon announces itself. This time it does nothing. So - alas - scrap dragging the score as a possible solution…
Just to let you know. It didn’t help me either unfortunately.
Well it’s good for Mark and bad for me, but I do have the same problem on my Mac. Even though I have all the settings in the preferences dialogue ticked, the playback line continues to move, but the score doesn’t move anymore to follow it and it scrolls out of view. Dorico is the only open application running. I tried with different Zoom Lives and different page views, but nothing changes.
Regards Jürg
So there are more than a handful of users having this problem.
Not really 
Not much can be accomplished for my style of composing: I have no formal training and do need to see and hear my scores as they are played back.
That’s not feasible when the bug is active, alas; it’d be interesting to know what some of us have it and and others do not.
I’m sure the team will have an answer soon .
I’m sure the team will have an answer soon
My answer right now is sometimes working too:
Sometimes it helps to quit Dorico and restart the score …
Jürg
I was going to ask this same question about Dorico 2.2 when the replies got me thinking (for a change) and I tried going from Page View to Galley View. The green line worked fine there, and the score was visible right to the end. BUT when I went back to Page View it worked fine, changing pages along with the green line. I don’t know if this will work for everyone (or anyone) else but it seems to be working for me.
Chet
I’ve tired that; have also tried resizing the window; Saving and reloading the file; quitting and restarting Dorico; and experimenting with several other (combinations of) variables.
None of that, alas, banishes the bug consistently.
We’ve found a bug recently, where the playhead stops following the score, if new music is added to the end of score after the first playback.
If you add music to the end of score before the first playback, everything should be fine, the playhead follows the score to the end for the first time. But if you add (enough, usually more than four bars) more music and play it back again, the playhead will move out of the view, as soon as it reaches the newly added bars.
This pattern is hard to recognise because sometimes changing layout or page view/galley view resets the relevant states. I think it can also be triggered by inserting music in the middle of the score in which case the playhead leaves the view as soon as it reaches the inserted music.
I wonder if this is what you experience?
András,
Congratulations on this progress!
I am still experiencing the bug.
When you say ‘first playback’, do you mean only the very first time a score is Played in Write mode?
And that it is the very act/process of adding bars at the end which is confusing Dorico, which is (perhaps: this is what I gather from your post) causing it to lose or otherwise incorrectly set (pointers to) the correct position for the playhead (from that moment on)?
In general terms, this would seem to be what I for one (others may have different experiences?) have noticed.
Though with the exception of the fact that my workflow is always:
Is this consistent with what you have found?
It may be that the bug surfaces only after one playback (does that have to be the complete score composed so far in your investigations?).
And I’d have said that I lose the Playhead more frequently the longer a session progresses.
But I’m sure that it - although it probably does happen after first playback - I rarely get the bug every time I play back; regardless of where I edit or add.
Please keep your discoveries coming: I’d love to help you track it down. And thanks again!
We believe the problem is fixed in our development builds, as described by András above. Every time you add enough music that a new system is added in page view, or new bars are added in galley view, then the score will only be followed as far as the last system (or chunk of bars in galley view, which doesn’t have systems of course but which Dorico splits into chunks internally). Saving, closing and reopening the project will alleviate the symptoms, until you add enough new bars that a new system is added.
As I say, this problem is fixed in our development builds, so I am confident you won’t experience it again after the next update is released, whenever that may be.