I've been following various online how-tos to get VNC with resumable sessions working. I can connect, but apparently without any window manager as I just get a grey screen. I've had this behavior through multiple versions of Ubuntu and figure I must have a bad config setting somewhere. Current set up:

Ubuntu 12.04.2 LTS
Lightdm
x11vnc

Does anyone have advice on how to troubleshoot this? I'm not coming across anything obvious in the logs.

Thanks!