how to stop the layout changing when updating tables via reverse engineer?

Hi, we already have a large data model in sqlDBM, with all the keys and relationships established. We have then built a part of the database and I am looking to update the sqlDBM model with the reverse engineering function. The tables update successfully, but the entire layout is changed, making it unreadable. Is there any way to have the existing layout unchanged, and just update the objects where they are in the diagram?