"Unable to connect to dbus" when run some gnome apps when su to root in a terminal window

T510 ~ # xhost
access control disabled, clients can connect from any host
SI:localuser:gbiglow

T510 ~ # xhost local:root
non-network local connections being added to access control list

T510 ~ # xhost
access control disabled, clients can connect from any host
LOCAL:
SI:localuser:gbiglow
T510 ~ #