MySQL Workbench, how to refresh EER diagram?

From the MySQL Workbench 5.2 window, select Database -> Synchronize model which will allow you to synchronize the model (EER diagram) with the database (you need to create a saved connection) for it.

I recommend this method over just reverse engineering the model from the database since it maintains the layout of the EER diagram. One caveat is that you need to add new tables to the EER diagram manually.

One thing to be careful with 'Database' -> 'Synchronize' is that it defaults to applying the diagram changes to the live database, i.e. it is suggesting statements such as:

DROP TABLE IF EXISTS h2.Import_Homol

Be careful to change this default behaviour if you are just using the EER tool for output diagrams, or your live tables will be dropped if they don't exist in the model (as will additional columns or any other schema changes).

http://dev.mysql.com/doc/workbench/en/wb-database-synchronization.html