Another case where the SSMS GUI failed...

Bug in SSMS where page level locking is disabled.

http://www.interworks.com/blogs/bbickell/2010/05/10/sql-server-index-indexname-table-tablename-cannot-be-reorganized-because-p

Whereas, if the SQL DDL command to create the index was coded by hand, the coder would know exactly what they were doing.

And when the object was reverse-engineered, so that it can be properly checked into the source code control system, was this error by SSMS going to be detected? I doubt it.