hate to re-open this as original poster's solution was very specific to his case; but the replies added here do apply to my case.
i have exact same issue:
- when app is running in foreground or background i get notices fine.
- if i do a force stop of my app then i do not get notices showing up on notification bar
i do have message field filled in. I didn't have a title in my msg but i added one and no help. I am using a Samsung Galaxay Tab 4 running Android 4.2.2 and i used the tutorial from devgirl posted above as the basis for my app code.
i am not sure if this is h/w dependent? i looked at a couple other apps, like FB Messenger.. and found it would not allow me to stop it. Perhaps that is the trick around this?