My project used to be fine - errors showed up in the file margin, the editor breadcrumb, the problems view and in the package explorer tree as little red X marks.
Somewhat spontaneously though, it's stopped working properly.
If I introduce an error into my code, it shows up in the file margin, and nowhere else. It takes a 'project clean' to make the red X's show up elsewhere.
Then if I fix the problem, the error is cleared from the file margin but the red marks persist elsewhere until I do another clean.
Why is it no longer showing errors properly in an automatic way?
I'm using Eclipse 3.5
Did you uncheck Build Automatically?