When I expand 'scala-library-2.8.0.RC3.jar', it is empty, and the expansion arrow disappears. When I switch focus away from IntelliJ, the arrow re-appears. Classes from the Scala library are not resolved and marked red.
I selected the JAR, copied the path with ctrl-shift-c, then unpacked to a temp folder
/tmp/scala-lib: jar xvf /Users/jason/.m2/repository/org/scala-lang/scala-library/2.8.0.RC3/scala-library-2.8.0.RC3.jar
I added this to the library definition, and the contents are browsable, and the classes are resolved properly in the editor.
The JAR from came from: http://www.scala-tools.org/repo-releases/org/scala-lang/scala-compiler/2.8.0.RC3/scala-compiler-2.8.0.RC3.jar
I think this is the same problem reported by Adrian Powell on scala-user.
Any ideas what could be causing this?