Please vote for this long standing bug to it on the radar - http://youtrack.jetbrains.com/issue/RUBY-11202 Thanks!
When you have multiple classes with the same name that are namespaced. Using 'Goto declaration' goes to the wrong class. Contrived example:
class FooController < Api::BaseController
When I click on the text 'Api::BaseController' to navigate, instead I get to Admin:BaseController. It looks like the IDE is going to the first match of 'BaseController' instead of taking the full name into account.