[ALUG] .profile *never* executes

I thought I understood (vaguuly) the reasons for .profile and .kshrc or, for bash, .bash_profile and .bashrc but on this new Fedora system it doesn't work as I expect. The system boots and runs gdm which allows me to log in and, as far as I can see, my .profile (or my .bash_profile) *never* gets executed. Surely it's supposed to get executed at least once when you first log in, but it's not getting executed here for me. If I ssh into the system then the .profile gets executed (as expected by a 'login' shell), but isn't gdm (or kdm, or xdm) meant to do the login shell bit for you before starting your window manager? -- Chris Green