At the moment I do not have any system here with Trinity installed configured for a graphical login. I have only command line logins configured: I better fix that for testing!
When using a login manager and a graphical login, the user's default desktop is defined in $HOME/.dmrc.
What does that config file contain when the user selects Trinity as the default? Does Trinity set $HOME/.dmrc like this:
[Desktop] Session=kde
Or like this:
[Desktop] Session=trinity
Thanks.
Darrell