Layout mess after entering a single note

Somehow the layout keeps on changing while I enter some new notes in a bar in the middle of the page. Is there a way to prevent this? Here are a before and after screenshots while entering a single 8th note in a bar:

There is a way to prevent it, but you may not want to—what you showed as your example looks to me like Dorico just doing its job.

When you added that 8th note, you forced an additional entry in that bar (the resulting 8th rest), which was just enough extra space to push the last measure of what had been your fifth system onto a new 6th system. Since it’s clear that the piece isn’t over, what you’re seeing is just an interim spacing situation—as you add more music, Dorico will keep evening out the spacing and the systems.

If you DO want to prevent that happening, the way to do it (and I really don’t recommend this when you’re still doing initial note entry) is to use Make Into System (Engrave Mode) to keep each system relatively stable, even when you add entries. That will allow a certain amount of additional note entry in a given system without triggering the creation of new systems, although if you add enough entries to “overload” the spacing, the system will eventually break anyway.

But if you do that while you’re still doing note entry, you’ll end up with a whole lot more work in your final layout stage, undoing all those earlier system decisions.

Based on what you’re describing, it seems to make sense to just let Dorico do its work, and don’t worry about system layout until the last step, after the note entry is completed (other than very minor tweaks that won’t significantly affect spacing.)

The piece was already completely done, layout-wise. All I wanted to do was correct some notes in that bar. So in this case, make into system would indeed be a good option. This is how I do this in Sibelius, I should have thought about this option in Dorico… Thanks!