Proper Way to Get SBT to Update External Dependencies? Follow

Just a general question.  I had a Play 2.1 project that I have upgraded to 2.2.  The original IntelliJ project was improrted as a result of running gen-idea SBT plugin and importing that into IntelliJ.  However, during the upgrade process of Play 2.1 -> 2.2,  I noticed when I removed the old Build.scala and added the new build.sbt to the project, I couldn't get the project to recognize this fact.  No matter what I tried, the External libraries were still pointing at the Play 2.1 related JARs.  I have noticed on other SBT projects, when I change dependencies in the .sbt file, it auto updates.  So, I sort of expect it to notice the new build.sbt and do the right thing.  Ultimately, I had to destroy the *.iml files and re-import the project as an SBT project.  I know SBT support is brand new - but wondering if there was a different (and more preferred/less destructive) way to do this in the future. (though I do expect this isn't a major issue moving forward - just a slight issue with getting existing projects onto the new platform)

In general, The Scala/SBT plugin is working great for me on IntelliJ 13 - I'm very greatful for all the hardwork the team has been putting into the plugin.  Thank you for rescuing me from Eclipse-hell. :)

-t