Perhaps, but I am not sure we need an editor at all. I read Matt's wishlist, and while I cannot disagree with the points he raises, I am just not convinced it would be a cost effective addition to the product.

Considering how few times it would be really useful, I would prefer PGMusic worried about more pressing functionality. Unless you have incredibly poor typing skills, simply retyping the problem cell should not be difficult. I would agree that highlighting a bad or unsupported chord might be helpful, the fact that your entry is not accepted should be enough to trigger a corrective action.

BIAB for Windows Version 2019 (643)
Windows 10 (1909)