EditorTextField in #3403: How to get an Editor that does error highlighting?

Hi,

yesterday, using build #3401 the world used to be OK. After fiddling around how to get a
ComboBoxEditor that does error highlighting, I came up with this piece of code:

final PsiFile file = parserDefinition.createFile(project, "DummyFile"")
.createPseudoPhysicalCopy();
final Document document = PsiDocumentManager.getInstance(project).getDocument(file);
final EditorTextField component = new EditorTextField(document, project, fileType);

Today, using #3403 and exactly the same code, I'm kinda lost because the code I was
looking for quite long doesn't work any more. I need some advice... desperately ;)

Thanks,
Sascha