Add VSCode Extension Preview Errors?

Currently, if one has a DBML file with errors in the table definition, the VSCode Preview won't render the erroneous DBML but instead renders a sample diagram. This is a valiant effort to render *something* but I think perhaps just some red text saying "Cannot render - fix DBML errors and reload" might be more direct, especially for first-time users. Not saying the current behavior is wrong per se, it just isn't quite obvious what's happening.