Eclipse will not validate print field column value

In Eclipse 4.6.2 I tried to put the 80 character print margin indicator string using Preferences -> General -> Editors -> Text Editors -> [Checkbox] Show Print Margin. However, no matter what value I put in the Print Margin Column, the row stays at column 120.

I'm pretty sure the line I'm looking at is the print margin because I can change its color in the same settings page. I hit Apply and restarted Eclipse but no luck.