I'm using pgAdmin 1.12.3 on Mac OSx. I have functions that use a Type rowtype to hold the results of a query. When I change the query to add/remove columns, I also change the Type, then do a drop, then create, and get a success message. However, I then need to drop and create all dependent objects, including functions. If I don't, users will get an error. Refreshing the database in pgAdmin shows the type has indeed changed, but users will still get an error until I drop and create the affected object (function).
Earlier versions of pgAdmin would give an error when dropping a Type, letting me know what objects were dependent on that Type. I would then do the drop with cascade, then create the function(s) affected.