I couldn't find a kxstudio bug tracker (happy to be pointed in the right direction), but even after running dbus-launch, the /tmp/dbus-$whatever file doesn't exist. Any clues?
antony@cubase:~$ dbus-launch
DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-QQxdgcZliW,guid=5189ae91141717bf527ffc355a0a0568
DBUS_SESSION_BUS_PID=12429
DBUS_SESSION_BUS_WINDOWID=37748737
antony@cubase:~$ cadence
Using Tray Engine 'Qt'
(process:12609): GConf-WARNING **: Client failed to connect to the D-BUS daemon:
Failed to connect to socket /tmp/dbus-qr6VFNSOMQ: Connection refused
Traceback (most recent call last):
File "/usr/share/cadence/src/cadence.py", line 2315, in <module>
gDBus.bus = dbus.SessionBus(mainloop=gDBus.loop)
File "/usr/lib/python3/dist-packages/dbus/_dbus.py", line 211, in __new__
mainloop=mainloop)
File "/usr/lib/python3/dist-packages/dbus/_dbus.py", line 100, in __new__
bus = BusConnection.__new__(subclass, bus_type, mainloop=mainloop)
File "/usr/lib/python3/dist-packages/dbus/bus.py", line 122, in __new__
bus = cls._new_for_bus(address_or_type, mainloop=mainloop)
dbus.exceptions.DBusException: org.freedesktop.DBus.Error.NoServer: Failed to connect to socket /tmp/dbus-qr6VFNSOMQ: Connection refused
antony@cubase:~$
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