1. Maven includes module A
2. Module A has dependency on B and C, but B and C are not included in the Idea Maven Project, only via mvn reference from A
3. When navigating to the class in module B all reference to classes from the module C are red even though both B and C classes are implicitly on the Idea Project classpath via A
When Ctrl+click on the class which is on the IDEA-MAVEN project classpath but the maven module containing the clicked class is not explicitly included in the Maven Project, idea navigates to the class from the jar in the class path which is OK. All references to the classes which is in the IDEA classpath but not referenced from that particular maven module are red.
In this case idea should look not only on the classpath of that particular maven module, but rather on the Idea current project classpath.
I realize that explanation is somewhat cumbersome :)