Hello,
I have an issue on Ubuntu Mate (16.10): as the title says, I am unble to make it display my user background on the LightDM screen. The option to do so is active in the LDM Gtk Settings Manager and I can’t find anything in the conf files (either in /etc/lightdm or /usr/share/lightdm) that would prevent this behaviour.
It’s worth noting that I don’t have the same issue on Xubuntu and it happens on Ubuntu Mate even when using a different Gtk greeter (and uninstalling Mate’s one, as it has a too high priority anyway). In fact, I have made my own Gtk greeter conf and it has the same behaviour: default background on Ubuntu Mate and user’s one on Xubuntu.
I suspect this may have to do with the default LightDM conf files on Ubuntu Mate (independantly of the Mate Gtk greeter, as the issue happens even when removing it), though I am unable to find where it could come from.
Any idea?