mmhh also a fresh new install is not fixing my issue
Sorry to hear that. 
Do you see the CEC adapter settings now? They must be somewhere.
I'm asking, because you maybe do an undesired repeating when you hit the power button.
The CEC adapter settings can fix that, because timing for repeating etc. is adjustable there.
also with a new install, at Settings -> System -> Input -> Peripherals is still empty
i also now have a GRAB FANART ERROR, at start up
Do you use the default skin? Please always do so for testing.
Because some custom skins let menu entries disappear.
at LE9 i use Aeon nox silvo (standard supported bij LE9)
It's maybe part of the official repo, but that doesn't mean it fully supports all LE standards. Most add-ons are made by people, who are not developers of the LE core.
Please use the DEFAULT SKIN, and try again. 
Also at standard skin Estuary the same problem GRAB FANART ERROR
Also at standard skin Estuary the same problem
OK, then disable "fan art" at Settings -> Interface -> Skin -> Configure skin... -> Artwork.
Then check the content of "Peripherals" again.
mmh can not find the artwork disable function
First entry at the Artwork menu should be about "fanart". Disable that.
Hello.
Doing some research i have found out someone has my same issue with the power button.
I have a fresh install of 9.1.502 on a generic pc using a wireless remote MX3.
I have tried all "fixes" found but none worked.
The power button activate Power Window and standby at the same time.
I can correctly remap most of the keys.
Any advise?
The power button activate Power Window and standby at the same time.
Did it worked on LE 9.0.x?
What happens when you map the power button to <power>noop</power>?
What happens when you remove the power button mapping?
i had the same problem with libreelc 9.2.6 installed on a notebook HP dv6000 that have a proprietary remote.
when i pushed the remote power button for the first time i noted a strange behaviour the he ActivateWindow(ShutdownMenu) pop-up and immidiately go to sleep mode
the first thing that i tried is to create a keybord.xml like this:
<keymap>
<global>
<keyboard>
<power>ShutDown()</power>
<sleep>ShutDown()</sleep>
</keyboard>
</global>
</keymap>
with this modify the he Activate Window(ShutdownMenu) stop to poping up but the system goes immidiately in sleep mode.
so i had the idea that the problem was in the linux part a i create lid.confd file with the command:
nano /storage/.config/logind.conf.d/lid.confd
and inside i wrote this:
[Login]
HandlePowerKey=poweroff
HandleSuspendKey=ignore
HandleHibernateKey=ignore
HandleLidSwitch=ignore
PowerKeyIgnoreInhibited=yes
i rebooted the pc and finally it work like i desire when i press the remote power button now the system shutdown completely
hope it help
