How to add a time signature without losing system breaks?
I'm currently writing a long file made of 12*7 cantus firmus (for Counterpoint studies). To achieve this, I already have set one system per cantus firmus. Each 10 bars, I set a system break in order to the new cantus firmus to start at the left of the page, which is more convenient. Now I have to deal with time signatures. The problem is when I drag a time signature on the first bar of a system, it automatically removed all my system breaks, which is annoying.
Is there a way to put a time signature without losing all the system breaks already in place, please?
See pictures below: the first before inserting a time signature, the second after. You will notice that I also lost all the final barlines placed at the end of each system. So my question also concerns final barlines.