I'd like to show errors (HighlightInfo set by TextEditorHighlightingPass) in the Problems/Project Errors tab. Errors may belong to several files in a project, so need to show them all as a tree. Noticed in your code (isInSourceContent in HighlightingErrorsProvider) that you check that files must be a part of sources to do so. Is there a way to avoid this check? Didn't find any appropriate extension point for that.