Since installing the latest backport kernel in Squeeze, kdm-trinity 
login screen shows this:

Press Ctrl+Alt+Del to begin

This process helps keep your password secure

It prevents unauthorized users from emulating the login screen

I seem unable to find any info on this behaviour, least of all how to 
disable it. Aside from a general annoyance I can't run a TDM virtualbox 
because that key combo will bring up the host's logout screen.

I prefer Squeeze generally but need a kernel => than 2.6.38 to support 
xz decompression

Any pointers to a solution?

David