Layout change when inputting 2 lyric line

Why does the layout of the second page changes when I input a second lyric line on the first page?
The layout gets messed up.

I think we’d need to see an example. Presumably when Dorico adds more space between some staves on page one to make space for verse two, it affects what fits on the page, therefore the spacing later on?
Maybe adjust the vertical spacing options in Layout Options, or ‘make into frame’ depending on the context / how much space?

Here is a file with which you can test what I meant.

Test File (384 KB)
By the way a found something strange:
When you copy notes of a bar via R (repeat) into the next bar which has e.g. a triplet in it then the triplet doesn’t get replace with the rhythm of the bar I want to repeat.

You have to include all of the triplet (not just the notes and stems) in order for the tuplet rhythm to apply.

Also see

You misunderstood me. The bar I want to repeat into the next bar has no tuplet. But the following one has a tuplet. And the trial to simply repeat the bar with the shortcut R doesn’t repeat the bar with its rhythm but the rhythm gets change because of the tuplet in the following bar.
I have just tried other rhythms and different tuplets in bar 2 with strange results. Once bar 2 got delete and was empty after hitting R and sometimes only some notes got deleted.
Just try it. You will see what I mean.

Adding a new line of lyrics causes the casting off to change because the program then estimates that more vertical space will be required.

Tuplets are not overwritten when you use R to repeat or Ctrl+V to paste. This is to allow you to do things like scale pasted music into tuplets. You can always delete the tuplet either before or after pasting or repeating, since deleting the tuplet will not delete the notes contained within it.

I unterstand what you mean. But this behavior is not correct at least not for me. The program shall give more space on the 2nd page when I input lyrics on it but not when I input on page 1. There are situations where I only have to input a second line on page 1 so the layout on the following pages should not be changed.

I see but I have also experienced that notes get deleted when repeating a bar.
Here is the file with instructions.
Test Chor mit (358 KB)

Because the layout of the score adapts to everything you do, you should find that the layout becomes stable once you have input more of your music. The way vertical spacing works is that Dorico uses estimates that it feeds into the casting off process during spacing. The circular and recursive nature of casting off (that you can’t work out what bars fit onto a system until you know how wide they are, and you can’t know how wide they will actually be until you know how many bars will fit onto the system) means that we have to make some assumptions up-front, and one of those assumptions is that if you introduce a second line of lyrics, we need to make room for it on all systems. This is not something we’re likely to change.

But, as I say, as you input more music and Dorico’s estimates about how the score will eventually be laid out get more accurate, you should find that the layout stabilises. Even if you end up with a layout that you don’t 100% like, plenty of tools are provided to help you to change it.

Regarding your repeat with R issue, can you tell me in a bit more detail what you expect to happen? Your 3/4 bar is actually a pick-up bar of only 1 quarter in length, so I would expect that the music in the bar following the 3/4 time signature is also overwritten when repeating four quarters’ worth of music, which is what is happening for me. Perhaps you could attach a screenshot of the result you’re getting?

If you delete the 3/4 measure mark then you get the same optical result as in bar 8 and 9.
But when I repeat bar 3 with R the notes in the following bar get deleted but this doesn’t happen when I repeat bar 8 with R shortcut.
So consequently I expect the same on both situations.