one of the biggest broken windows with the Eclipse Scala IDE is its lack of an effective coverage tool for scalatest test (especially when compared to IntelliJ).
Yes I know that you can use EclEmma to analyze Coverage on scalatests that are run as Junit tests, but that has issues.
One is that its a workaround to do that. Most scala developers want to run scalatests as scalatests and not as junit tests.
Two is that EclEmma struggles to accurately report coverage on scala implementations that use case classes and/ or companion objects. (though the line by line coloring is more accurate than the charts in the coverage view)
As mentioned above this is one of the biggest functional gaps I see with eclipse's Scala IDE as compared to InteliJ's IDE and adding an effective native scalatest initegration for eclEmma really should get high priority attention