7.0M2 error highlighting breaks if you paste in a piece of code that references other classes and then click Cancel in the dialog prompting you to import the classes automatically, e.g.: copy and paste this from one file (where these are all classes defined in my project): public IntervalCategoryDataset createDataset (LogisticsInventoryResult liResult) { long [] minMax = getWindow(liResult); Set<Resource> resourceSet = populateKnownResources(scheduler); } into another file: package foo; public class Test { } to get this, but cancel the import dialog and nothing shows up as red package foo; public class Test { public IntervalCategoryDataset createDataset (LogisticsInventoryResult liResult) { long [] minMax = getWindow(liResult); Set<Resource> resourceSet = populateKnownResources(scheduler); } } } If I do the import the highlighting works correctly. If I run idea.bat (with JDK 1.6) I get a number of exceptions in the log - if you want that.