default display manager in Ubuntu 16.04 + trinity

Hi I have recently installed trinity on Ubuntu 16.04 in two ways 1. Installing Ubuntu 16.04 first and then add the trinity repos 2. Using the livecd. There are subtle difference. One concern the default-display-manager In both cases I have set it to /opt/trinity/bin/tdm But while the login screen looks relatively modern in the first case (it has the log of powered by trinity), the second installations log screen has the charme of the 90, no offense intended. Any explanation for this behaviour? Regards Uwe Brauer