[Cykasm]

I have absolutely no problem with kodi 17.6 ( kodi stays in full screen when I switch off/on my tv , problem occurs since kodi 18 beta)
I also tried kodi 18 nightlies , it s the same problem

The same for me:
HTPC (TV connected over hdmi) has no problem with Kodi 17.6, when TV is switched off an on again. Full sreen works.
HTPC (TV via HDMI) has problems with Kodi 18 rc1-rc3 when the TV is turned on and off. Full sreen disappears after switching the TV back on.

Turning the TV on and off is needed to listen music streams without the TV is running.  

Exact same for me too.
Never had the issue with 17.6, but V18 changes resolution and doesn't recover.
Rest of the desktop is the correct resolution. I may have to downgrade back to 17.6.

[Zokkel]

Please test this build

https://forum.kodi.tv/showthread.php?tid...pid2818311

Make sure to disable the DPI override if you enabled it and let us know if it works for you.

[Cykasm]

Will install today while at work.
Won't know the results until I get home Sunday.

Thanks for the follow up.

[Cykasm]

Couldn't edit, but got curious and tested before I left for work. Worked for me.