Hello!
Is it possible to fix the measures in Dorico to say 4 / line like in Finale? How do I do it?
Dorico doesn’t currently have a feature to fix a certain number of bars per system. You can insert system breaks in Engrave mode (select the note at the start of the bar you want to start a new system, and type Shift+S).
Is there a way to do this (and other, related tasks) without memorising the needed key combination - like eg with contextual menus, other menus or something similar?
In engrave mode, break system and make into system are tools easily accessible on the left panel (Format Systems) ! So if you are reluctant in learning the key combinations, those essential features are just one click away 
Ok, new question same topic:
That works if I have too MANY bars somewhere. Dorico decided now that my song should have only three bars on the top. How do I fix that? If I want one more bar to jump up one level?
There is something like “make into system” (Engrave Tab)
Yeah that works sometimes, but the program doesn’t want to make some of the bars into system. It’s like I can’t really decide for myself. This fucks me up.
Dorico should always allow you to tell it which bars you want on which systems. Make sure you select the first note in the first bar you want to be at the start of the system, then select the last note in the last bar you want to be at the end of the system, and choose Make Into System. That really will do it. If it doesn’t, that sounds like a bug, so I would need to see your specific project along with details of which layout you’re looking at and exactly what you’re selecting before you use Make Into System. You can attach a project here, but you need to zip it into a zip file before you try to attach it. Thanks!
That solved it. Thanks!
Now when i continue writing and engraving at the same time, the program usually redraws the staff spacing when I add new bars. This messes up the paper and I have to re-do the spacing over and over again. An solution?
I believe the whole concept of Dorico is that you do not write and engrave simultaneously. First write, then engrave. If you are working against the design of the program you are bound to experience inefficiencies.
I think that’s the concept of most notation programs. There’s an order in which things work best, and applying the finishing layout touches to a document is one of the things best left until the last, certainly well after entering the notes. I wouldn’t try painting a house until after the walls are up!
I agree with the others who have suggested that it’s best to enter all the music before worrying about how it will look on the printed page (thus the two different modes “write” and “engrave” in Dorico).
However I have noticed an icon on the left in Engrave mode which has a picture of a staff with a lock in the middle of it. When I mouse over it the popup says “lock system” – perhaps after you’ve got a system looking just like you want it, you should select the whole system and then click that icon. Do that for each system you’ve got just as you want, before entering more music, and my guess is that the earlier systems won’t re-draw themselves, altering the layout you’ve already done.
Ok thanks again for good answers. I guess you’re all right about the order of how to do it. I’m pretty new to notation software in general.
dhbailey52 I should try that as well! Thanks!