Problems scope does not list all compile errors after 'make project'

Using 11.1.1

My understanding is that Project > Scope: Problems should list at least all compile errors (and warnings?) that exist ATM. I am looking at a class in the editor where one non-void method is missing a return statement. The class name is highlighted red; there is red tick-mark next to the line of code in question but this class isn't listed in "Problems" scope. Why?

Build->Rebuild Project shows a 'Messages Make' panel at the bottom of the screen with dozens of compile errors (across multiple classes); but the Problems scope lists only one class. Is this by design or am I missing something? Screen shot attached.

Thank you,
-nikita