I am wondering what is the difference between a HighlightVisitor and an Annotator? I am using both of them and it seems that in both cases I can highlight a PsiElement with different levels and quick fixes.
The wiki page only mentions Annotators, but most of the error highlighting in IDEA is done in HighlightVisitorImpl.
Also, when I highlight errors in my custom language using Annotator or HighlightVisitor, the file is not underwaved (in tabs and in project view). Am I missing something? Is it possible to highlight files with errors for custom languages?