Extend the column toolstips with the nullable attribute
Extend the column toolstips with the nullable attribute, like this "ic.Attachment varchar(max) not null (Column)"
Franz Renesnicek shared this idea
This is included in SQL Prompt 6.4, which you can download from http://www.red-gate.com/products/sql-development/sql-prompt/
Dan Plaskon commented
Agreed, this would be VERY handy in places where column summaries are shown (in suggestions and the column picker, for instance).