Enable HiDPI on 23" iMac? I have a 23" iMac running Lion (10.7.3). I've checked that the "Enable HiDPI display modes" checkbox is enabled in "Quartz Debug" (it was checked the first time I opened it), but there are no HiDPI resolution options in my display settings.

Has anyone had success with using HiDPI display modes on a 23" iMac?
Per the instructions on the screen, you have to log out and back in when enabling or disabling HiDPI mode for the changes to take effect: