The current version of gdm ignores the
~/.xinitrc and the
~/.xsession completely which really surprised me, I thought it used them in prior versions.
The is mostly a problem when using ubuntu but there is a way to get this working. Gdm loads the .desktop files from
/usr/share/xsessions and offers them in the sessions menu, therefore the easiest way is to create a new entry for our xsession:
[Desktop Entry] Name=Xsession Exec=/etc/X11/Xsession
This will load our
~/.xinitrc as we expect it.