The current openbox stable will not start (from an .xinitrc and I imagine any X wm strat routine) with these two other packages installed. I currently run openbox with xfree-4.2.99.3 without problems. The emerge of Mozilla-1.2Beta caused the failure of X to start in anything but KDE. Openbox provided the following info: Xlib: sequence lost (0x10000 > 0x96) in reply type 0x0! Then there were messages about BScreen::Bscreen: an error occured with querying ... another window manager is currently active. I thought maybe I had stale locks / something else causing the problem, but I rebooted the machine and remove all of /tmp/* and the backed through my /var/log/emerge.log to see what had been added. As soon as I unmerged Mozilla it worked like a charm. Thanks
Try 1.2 stable, try 1.0.1 or any other version. If one works and the other not, let me know.
Like I said, try the stable versions, if still issues, reopen.