Hi KatL, thanks for posting on the Community. 

We appreciate the inconvenience that this change has caused for you and have forwarded this back to our product development team. As a workaround, depending on the information that you are trying to see, you may consider running a report. For example, custom fields can be added to the Customer Balance Detail report by selecting the small cog to the right of the report > show more > tick the custom field(s).