Moving symbols and lines messes up the layout

Dear Dorico team,
can you please explain what is happening in this video?

What I do is I move a hairpin on the right page, while in engraving mode. Suddenly the p symbol on the left page raises up to the sky, and a bit later with each move of the hairpin on the right page, the staves on the left page perform free choreography. Same story happens if I move any other symbol or line on any of these two pages.

I remember I experienced the same in Sibelius. Am I doing anything undesirable that both programs act in a similar way?

Welcome to the forum, terentyev. We’ll need to see the project file itself that reproduces this problem, please, if you could zip it up and attach it here, or email it to me at d dot spreadbury at steinberg dot de. Please include in your email or post here which layout to open, which bar to edit, and where the unexpected behaviour occurs.

The good news, such as it is, is that these kinds of problems are transitory: if you close and reopen the project, you’ll find the staff spacing has returned to normal. The precise reason why this kind of problem occurs always varies depending on the specifics of the project itself, which is why we need to see the project file, but in general terms, the issue is that Dorico has to perform collision avoidance over the range you edit; if the graphical range affected by the edit differs from the rhythmic range affected by the edit (because items are e.g. longer graphically than they are rhythmically, which can sometimes happen), then sometimes parts of the calculation for how far apart staves should be get left behind between edits, resulting in the program incorrectly thinking that the staves need to be further away than they really do. Each successive edit leaves the same little remainder behind, which gets stacked on top of the previous remainder, causing the gap to get wider after each edit.