When Openbox is installed, it sets up a session called GNOME/Openbox which is supposed to launch GNOME with the Openbox window manager. However, in F15 this doesn't work; you get a failure dialog which kicks you back to gdm. This is likely due to big changes in gnome-session for F15 / GNOME 3. The option doesn't really make much sense any more, as you can't run GNOME Shell with an alternative window manager. You can use an alternative in the fallback mode - compiz-gnome package has a working implementation of that (or it worked last I checked...) - but that may well go away in future (as fallback mode does). At a minimum, I'd say we should move this to a sub-package, and consider dropping it entirely. Note that Openbox is part of LXDE, so as soon as you install LXDE, this gnome+openbox entry pops up in the sessions list.
-- Fedora Bugzappers volunteer triage team https://fedoraproject.org/wiki/BugZappers
I filed this years ago as bug 520245 already, but it was closed WONTFIX. Claiming that the problem is only caused by the display manager that does not check TryExec to see whether a session is available no longer helps in GNOME 3. And this doesn't solve the problem of running openbox-gnome-session from the commandline in init 3 or from xinit. Both openbox-gnome.desktop and openbox-gnome-session clearly require GNOME, thus they should be in a subpackage that has proper dependencies.
The GNOME/Openbox session is supposed to start the classic gnome with panel and nautilus. It worked at least at one point, but apparently something have changed again. I think I'll just drop it, it was always a hassle to keep it working.
openbox-3.4.11.2-8.fc15 has been submitted as an update for Fedora 15. https://admin.fedoraproject.org/updates/openbox-3.4.11.2-8.fc15
Package openbox-3.4.11.2-8.fc15: * should fix your issue, * was pushed to the Fedora 15 testing repository, * should be available at your local mirror within two days. Update it with: # su -c 'yum update --enablerepo=updates-testing openbox-3.4.11.2-8.fc15' as soon as you are able to. Please go to the following url: https://admin.fedoraproject.org/updates/openbox-3.4.11.2-8.fc15 then log in and leave karma (feedback).
openbox-3.4.11.2-8.fc15 has been pushed to the Fedora 15 stable repository. If problems still persist, please make note of it in this bug report.