I need to automate apt-get installation of kde-plasma-desktop which winds up installing both kdm and lightdm Display Managers.
I'm using debconf-set-selections prior to installation to set the following values:
# Default display manager:
# Choices: kdm, lightdm
kdm shared/default-x-display-manager select lightdm
lightdm shared/default-x-display-manager select lightdm
However, when I run apt-get I still get prompted during configuration to select the default Display Manager. I've studied the configuration scripts for both packages, but still not getting it. They call db_input high shared/default-x-display-manager unconditionally, yet it only asks the question if there was a prior value for the question.
How can I suppress this interaction so it can be run unattended?