Implements Icon Not Showing On Interface

I have an interface defined in a JAR file that's a Maven dependency in a project. A class that implements that interface has the small "I" (implements) icon in the left gutter. However, upon navigating to that interface, I don't have the corresponding "implements" icons in the interface. I *thought* I remember seeing the icons in interfaces in JARs, but am frankly not sure.

Should they be there. If so, is there anything I can do to cause them to display?

Jack