Does X11.app process my ~/.xinitrc?
You may have a previous installation of X11 or XDarwin with a pre-existing ~/.xinitrc. The first time you launch X11.app after installation, it will ask whether to back up your existing ~/.xinitrc to ~/.xinitrc.old and use the standard /etc/X11/xinit/xinitrc. If you reply no, it will use your existing~/.xinitrc. If you reply yes, it will use /etc/X11/xinit/xinitrc (the X11 default). If neither ~/.xinitrc or /etc/X11/xinit/xinitrc are present, X11 for Mac OS X will use hard coded values that launch an xterm and the quartz-wm window manager.