MATE Power manager frequently displayes "Battery Discharging" notification, without disabling option

[Saverio Miroddi]

On my (MATE 18.04) laptop, the "Battery Discharing" notification is displayed very frequently (every minute, more or less).

I've tried disabling it, but this is not possible, at least, on my distro (MATE 18.04).

I'm somewhat confused, because the MATE power manager dconf keys of other MATE distros (ie. Mint) are signficantly more than the ones of my system:

```sh
$ dconf list /org/mate/power-manager/
button-power
brightness-ac
backlight-battery-reduce
button-lid-ac
button-suspend
idle-dim-battery
button-lid-battery
sleep-display-battery
```

This is also reflected in the GUI, which doesn't have any other option available.

I've attempted to set the `notify-discharge` key:

```sh
dconf write /org/mate/power-manager/notify-discharge false
```

but this doesn't help.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: mate-power-manager 1.20.1-2ubuntu1
Uname: Linux 4.18.16-041816-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.4
Architecture: amd64
CurrentDesktop: MATE
Date: Fri Nov 2 10:41:09 2018
InstallationDate: Installed on 2018-10-03 (29 days ago)
InstallationMedia: Ubuntu-MATE 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
SourcePackage: mate-power-manager
UpgradeStatus: No upgrade log present (probably fresh install)

[Saverio Miroddi (64kramsystem)]

I've found that the correct key is `notify-discharge`, which solves the problem.

This report is somewhat a mixed of two possibly still valid issues:

1. the kernel/firmware not correctly hanling ACPI events (the machine is a Surface Book)
2. a feature request for allowing the discharge notifications to be disabled.

I'm not sure how to proceed (eg. closing as invalid, or splitting one or more of the two issues...).

[Launchpad Janitor (janitor)]

[Expired for mate-power-manager (Ubuntu) because there has been no activity for 60 days.]