This works correctly on the Java 8 JVM. The likely problem is that you are running on a Java 7 install.
By these release notes ScalaFX has two parallel releases:
- v.1.0.0 - supports JavaFX 2 and Java 7 (SFX-1)
- v.8.0.0 - supports JavaFX 8 and Java 8 (SFX-8)
Either update Java, or use the other release.