This may be obvious to some but it wasn't to me so I thought I'd write about it. Recently I discovered a problem with our implementation of DbConnectionStringBuilder. Whenever you changed a field that took a string (i.e. character set or server), the connection string property would not update. I know the changes were applied because I developed a test application that queried the connection string. It was correct even though the UI of the property grid was not.
After an embarrassingly long time working on this I emailed a friend of mine who I felt would know the answer. Turns out he didn't but he knew someone who did and not more than 30 minutes after talking with him I had my answer. Each property of MySqlConnectionStringBuilder needs to be decorated with the RefreshPropertiesAttribute. This causes the property grid to refresh itself when they change.