It seems churlish to criticise what is an excellent FREE tool so this comment is made by way of observation. I am experienced in music theory/notation etc and have used commercial editing programmes but am lacking in memory retention. Is it possible to 'insert' a missing note which could then move the remainder of the notes along.? I have tried the arrows button but they seem to operate only from starting position and of course when you try to position your cursor somewhere else you get a note. Sorry if it's a dumb question.
If you click with the right mouse button on the position you want to add a bar you get a context menu with the option "Insert bar". I think that's what you are looking for.
Thank you -never thought of right clicking¬!!