Focus on staff feature

I would like to display only one instrument in the score editor, into which I want to record. In Sibelius it’s called Focus on staff. Is such a feature in Dorico?

While there isn’t a Focus on Staves feature, you can make a new layout pretty easily that has only the staves you want. Here is a good thread about it, from 2018 (version 2, so some things are slightly different now but the concept still works fine).

https://www.steinberg.net/forums/viewtopic.php?t=141883

Also, the “Propagate Properties” function that Daniel alludes to in that thread has since been implemented. Keep in mind that it only works on layouts that exist at the time you perform the operation: any new layout will have the properties reset to default.
Another caveat: keep in mind that enharmonic (re)spelling is not included in this functionality. It auto-propagates from score layouts to part layouts but not the other way around. So in order to stay consistent, make sure that your custom layouts are of the “score” type, signified by the little conductor icon in Setup mode. It can still be a score layout even when containing only one player.

I also recommend creating new layouts with only players and flows that you want to see. This has become a staple of my workflow with Dorico as it is so quick and easy.