[property editing] problem marker remains present after closing editor without saving content

[martinlippert]

Problem markers seem to remain present after closing an editor without saving the content. So if I have an error marker showing up (correctly) while editing the application.properties file and close the editor, then choose to not save the content, the error marker remains present (in the problem view). I have to re-open the file in an editor to get the markers updated (and therefore removed).

Not yet double checked whether the behavior is the same on VSCode or not (in case auto-save is disabled or hasn't happened before closing the dirty editor).

Maybe we need to take didClose into account for re-running the validation?