One should only button the middle button if/when more than one button is functional.
The Two Button Blazer:
The rules of buttoning the two-button single breast blazer are rather simple. Always button the top button. There are no exceptions to this rule. This jacket is very convenient for broader men; the slimming effect brought by a deeper V will lengthen your torso and make you look dapper.
The Single Button Blazer:
If you have issues or doubts about how to deal with a single button blazer, we recommend you fill the contact form on our Contact tab because you obviously need immediate help. The single button blazers are excellent for shorter men. The single button blazer will extends your torso making you look taller.