Theme on login screen different than during session

[Reinhard]

This one is driving me up the walls right now.

DM is lightdm, greeter session is slick-greeter, both preinstalled.
I got Onboard to show the same theme that I have been using during my session on my voyo vBook i7 tablet in "standard" Linux Mint 21 "Vanessa" Cinnamon, in my case modified "Blackboard", simply by adding the line

keyboard = onboard -t Blackboard [sic]

to

/etc/lightdm/slick-greeter.conf

Now I switched distros and went for LMDE 5 "Elsie" and it's not doing it anymore. I have tried changing the syntax to all thinkable solutions.
keyboard=onboard -t Blackboard
keyboard=onboard -t 'Blackboard'
keyboard=onboard --Theme=Blackboard
...

and so forth. I also looked into it in the dconf-editor and tried to change the schema in "/usr/share/glib-2.0/schemas" and recompile it with "sudo glib-compile-schemas /usr/share/glib-2.0/schemas"

It always shows the default theme (Nightshade)

What am I doing wrong? My OCD kicks in pretty badly :o

Cheers!

[Kanehekili (jentiger-moratai)]

It seems that slick-greeter as well as lightdm-gtk-greeter can't cope with the "draw-user-background" setting. It is not working, so you have to set it to false and create your own background image. WTF

[Reinhard (kellogs667)]

Hm, I'm not talking about the greeter background but about the theme onboard is using...

[Reinhard (kellogs667)]

OK, the weirdest update now:

Since I couldn't find a way to get onboard using my modified Blackboard theme I installed Lightdm-GTK-Greeter and was tinkering around with it. I couldn't get it to look proper with my HiDPI screen. However with the additional "keyboard = onboard -t Blackboard" I got onboard to look like I wanted. But I switched back to Slick-Greeter by setting up the greeter session back to "slick-greeter". Rebooted and...
onboard was using the Blackboard theme! There isn't even a line stating that in the /etc/lightdm/slick-greeter.conf
Couldn't find any mention of it!
I purged lightdm-gtk-greeter and all leftovers and it still sticks!
What the hell?

[Reinhard (kellogs667)]

I have figured it out btw.
It's not very elegant but it's working.

So step one is to create a new theme in /usr/share/onboard/themes It will not work with the theme stored in the home-.local folder. Don't know why and don't care atm

What I did is that I copied the one I was using from /home/ME/.local/share/onboard/themes to the /usr folder. In my case "Blackboard".
Rename it (has to be done with "sudo cp") to BlackboardMod.theme or whatever you deem fit. Open the copied file with Nano and change the name accordingly.

Then you go into your /usr/share/glib-2.0/schemas folder and look for an override file created by LMDE called mint-artwork.gschema.override
In it you will find the lines

[org.onboard]
theme='/usr/share/mint-artwork/onboard/Nightshade.theme'
key-label-overrides=['RWIN:Super:', 'LWIN:Super:']
status-icon-provider='AppIndicator'

The "theme" line needs to be changed to /usr/share/onboard/themes/BlackboardMod.theme

Secondly the slick-greeter sets its own default value for the Layout in the glib schema "x.dm.slick-greeter.gschema.xml"
Nano it, find the lines saying:
    <key name="onscreen-keyboard-layout" type="s">
      <default>'/usr/share/onboard/layouts/Small.onboard'</default>
      <summary>Path of the onscreen keyboard layout</summary>
    </key>

And change "Small.onboard" to "Compact.onboard" (that is if you're using the Compact layout at all. If not ignore)

Rebuild the schemas with "sudo glib-compile-schemas /usr/share/glib-2.0/schemas"

Reboot. Done.

*note*
Ayn changes from running onboard will not be carried over to the /usr/ created .theme file. It will only apply to the /home/ configuration. So whenever you change the settings in your currently running onboard instance the changes need to be manually carried over to the /usr/ .theme file