Customizing the metamodel : Diagrams: Creating and modifying : Creating roadmap-style diagrams : Property set : Milestone
  
Milestone
Milestone has a date property "Milestone Date".
Milestone has a number of list-based properties which record state information.
Milestone has "Following Color" property, which is a list-based property of color values – for example:
VALUE "White"      Depictions {fill color {255,255,255}}
Note If referenced with the Complete keyword, these cannot exist without the project and cannot be created independently.