I've recently developed an issue where the New -> Scala Class menu item is no longer appearing in the Project view under my test source set. It still appears under the main source set for the same module, though. This is with a Gradle project.
The only thing I can think of that might have triggered it was switching back and forth between two feature branches on Git. One of them did add a dependency on ScalaCheck to the build.gradle file, but otherwise the module's configuration should have been unchanged. Creating Scala files in test had previously worked under both branches, too.