
Now the settings manager from XFCE works for all the tabs and the "Log Out" menu entry runs @xaos52's bl-exit script (modified to work with bspwm), it's all very civilised

Here's the ~/.xinitrc (use ~/.xsession if using a display manager and select "Custom Xsession"):
https://gist.github.com/Head-on-a-Stick/f2f2d3b2a49ca06e58044493d85bbd28