Imports such as java.io.File, java.util.Properties, and java.util.regex.Pattern are red (specifically, the class name itself is red in each instance).
This is happening on both java-only and scala projects.
Therefore, with this latest update, the plugin is essentially unusable.
I'm using IDEA 13 CE 133.193, on JDK7 1.7.0_40 amd64.
There was no problem just before the update, when I was using the scala plugin v 0.26.323.