I observed this today for the first time in the latest release. We have a Maven module configured to run our Selenium functional tests. We use the Spring JUnit test runner so our POM defines all the Spring dependencies with a scope of test. When the dependencies are configured with test scope Intellij hightlights all the Spring namespace URLs red and flags them as unregistered. If I switch the scope of the dependencies to compile instead of test scope the error hightlighting goes away.