Push notifications missing when app in foreground, but device locked

I just did a testing, and I did receive the notification on my MX4 device. I did the following:

1) Install the "hello" from our Ubuntu store. It is a push notification client
2) Register an account with any name (nick) in the client
3) Open the webpage link at http://direct.ralsina.me:8001/

When the app is in the foreground and press the power button, On the webpage, just send a message to your client (to the nick). Then unlock the phone again, you will see that the message comes in and it is shown there in the app.

However, the problem is that there is no indication of the LED flashing or sound for the newly received notification. I think this is a must for a messaging app. An end user should not miss the reminding of the new messages.

Thank you for looking into this XiaoGuo. I will elaborate further on your comment, as it seems some important details seem to be missing.

> When the app is in the foreground and press the power button, On the webpage, just send a message to your client (to the nick).
> Then unlock the phone again, you will see that the message comes in and it is shown there in the app.

You will see the message comes in only because you turn the device back on. I saw multiple times (but not always!) the persistent notification would show up only *after* turning the device back on. Which misses the whole point of a notification concept.
Essentially, you're seeing the message show up in the app only because you just turned the device on.

> However, the problem is that there is no indication of the LED flashing or sound for the newly received notification.

There's no sound or LED or, occasionally, even no persistent notification for the newly received notification. When I tested this, I saw two different cases:
[before: device off, message sent, device stays silent even though it did receive a notification]
- I turn the device back on, and the notification immediately shows up (and is audible + LED)
- I turn the device back on, and there is even NO persistent notification (the one at the top), which is even more serious

To summarize: app in foreground && screen off == no audio/LED, possibly not even a persistent notification once screen is back on

PS When I mention lack of persistent notification, I mean I would expect the notification to show up (or at least highlight the messaging indicator) even though the app is theoretically in foreground, but behind the screen lock.

I am aware that when the screen is on and the app is in foreground, there would be no notification, but the use case covered by this bug is real.

Seems in client/service/postal.go it needs to check not just if the app is focused but also if the greeter is active and if so proceed with the notification.

Status changed to 'Confirmed' because the bug affects multiple users.