title: NSTextField with automatic NSNumberFormatter in Interface Builder
body: <p>I've been making iOS apps for awhile, but I'm trying my hand at MacOS development. I'm adding an NSTextField to my UI and I noticed in Xcode that one of the options in the graphical widgets is "NSTextField with NSNumberFormatter" which implies to me that I'll be able to restrict the input of the field to numbers and configure the formatter in some way. </p>
  
  <p>When I add the NSTextField with NSNumberFormatter to my UI, I can see it has a formatter outlet which appears to be kind of linked to an NSNumberFormatter (although the name is a little grayed out). However, I can't figure out any way to interact with or configure that NSNumberFormatter. </p>
  
  <p>Any help?</p>