Inside a non-Scala project, the Scala plugin adds the following non-applicable UI items:
1) When selecting a package in the project view to run all tests, options for Specs, Specs2 and ScalaTest are provided.
2) In the editor tab context menu, an entry "Convert Java file to Scala" is appended at the end.
Issue #1 is moderately annoying (it adds an additional UI step in the process of running all tests in a package).
Issue #2 is trivial, but would be nice to fix. I've "converted" a few times by mistake, instead of hitting the "Subversion" entry that used to be at the bottom.
I assume both of these could be resolved by a simple guarding if, checking for the presence of a Scala facet anywhere in the current project (or something like that).
Again, the current project has not a single line of Scala or anything remotely related to Scala.