GRUB_MENU_PICTURE variable seems not to work under Ubuntu 17.10

[zako]

I've selected a background image on "appearance settings" tab. After click "save", I noticed that the image path was written to a variable named "GRUB_MENU_PICTURE" in /etc/default/grub

export GRUB_MENU_PICTURE="/boot/grub/dota2.png"

However when I checked /boot/grub/grub.cfg there was no background image. I also used grub-mkconfig to generate grub.cfg manually and there was no hint like "Found background ..." as it should. It seems that grub-mkconfig do not use variables named "GRUB_MENU_PICTURE" or "WALLPAPER"(as /usr/share/desktop-base/grub_background.sh indicates).

Currently I could only set GRUB_BACKGROUND variable in /etc/default/grub manually.

Version Numbers:
Ubuntu 17.10
GRUB2: 2.02~beta3-4ubuntu7
Grub Customizer: 5.0.7-0ubuntu1~ppa1a

[Daniel Richter (danielrichter2007)]

I can't reproduce the problem. It works well on a fresh install of ubuntu 17.10.

Do you have some shell programming skills? Then try to debug /etc/grub.d/05_debian_theme (but don't run it directly, always use grub-mkconfig or update-grub).