This may not be the answer you're looking for, but I long ago abandoned trying to use the notation function in BIAB.

I just can't get on with it at all and instead use notation software (I use Sibelius, but there are plenty to choose from without having to pay) which I then then import into BiaB.

It does mean that any time I want to adjust the notation, I have to do it in one program and then import it into BiaB, but I still find that a lot easier and quicker than trying to use the BiaB notation function.

You might not want to go down this road, but I just wanted to raise it as an option.