How to change the action of NSColorWell?

I can use NSColorWell as button to change the color of selected text. Since NSColorWell is object of an NSControl it has target and action. I guess, the action is implementing the code to change the color of the selected text in NSTextView. Where can I find this code for NSColorWell action? I would like to change it in away that I can use NSColorWell to change the background of the selected text, and ultimately to have in ToolBar two NSColorWell buttons: one to change text's foreground color and second one for text's background color.

NSColorWell is just a rectangular control to change a color.

• You can either create an IBAction and connect it to the action of the color well in the Connections Inspector (⌥⌘6) of Interface Builder

  @IBAction func changeColor(_ sender : NSColorWell)
  {
     let color = sender.color
     // do something with the color
  }
  

• Or bind the value in Bindings Inspector (⌥⌘7) of Interface Builder to a dynamic property, this example will set the color well to a default value of green.

  dynamic var color : NSColor = .green {
     didSet {
       // do something with the color
     }
  }