Prevent shifting on other staves when working on a staff

I’m entering a score that has some spatial notation, alternating with measured sections.
As I work on (and struggle with) inserting notes in a measure, I’d like to have the music on later systems stay aligned as already measured.
(I wanted to attach the score I’m working on but it wouldn’t let me attach the .dorico or .pdf file.)

For example, I’ve entered the vocal line so that it goes into 3/8. But I need to add another quarter at the end of the unmeasured bar to make room for the piano flourish. Then I have to move the barline and time signature so that the vocal line is correct again, which also undoes the Force Duration thing I managed to do for two dotted eighths in 3/8 time.

Conceptually, I think of barlines like anchors in unmeasured music and I want the music to stay within the barlines as I insert new material in a particular measure. Am I thinking about this wrong?

Thanks!

I should amend my title. Shifting on any staves, including the one I’m working in.

To post a Dorico or PDF file, you need to zip it first.

Here’s the file I’m working on. Thanks, Derrek, for the tip.
pjm-ChillWindinAutumn.dorico.zip (361 KB)

I may be understanding you incorrectly - but I was able to add some notes in your unmetered bar using Insert, in Write mode (it’s in the left toolbar, just above the lock icon). But that will throw your following 3/8 section off.

So first, I added another bar (or bars) of 3/8 by clicking on the first 3/8 bar, typing shift-B and then +1 (or however many bars you want). Then you can turn on the Insert command and add more music to your unmetered bar; delete your first 3/8 bar, and put in a new 3/8 meter where you want it to go. A little complicated but it works. Is this what you’re trying to do?

Try the “make into system” or “system break” options on the lines you want to be unaffected. Then anything you do before them will simply push them down, but not shift any notes into the system (and thereby preserve your spacing.)

Thank you for the replies. I did use a combination of those techniques. It was still tricky when I had more than one voice on the staff, but I finally got everything lined up. I see that I have to get some different concepts in my head to make the note entry go more smoothly. I started with a more tricky piece, but it forced me to learn. The next movement is in 4/4.