Good.
More ideas, about error dialog:
§ Error dialog should state file and region, and make sure that file is opened, brought to front and scrolled to error position.
§ Idea: for some errors like "Symbol already defined", it would be nice to have button there: [search all files for that]
§ Maybe optionally allow to edit without closing error dialog. (so user do not forget what it was about when interrupted by phone/whatever)
Well OK it is possible to mark error dialog content and copy. Maybe a button in that dialog: [Copy to clipboard]
(Another method: I had another program in windows before that opened all output listings including errors in separate files shown by simple text viewer.)