I just disabled xfwm (the xfce window manager) and xfdesktop through the sessions and startup setting. I added i3 as a startup service. I also deleted all keyboard shortcuts. . I kept the panel though because its very convenient for starting qubes. Now the icons for device management and other stuff moved down to the i3bar and.tiling works fine. Like the best of both worlds.
When i used pure i3, the qubes management window would have horizontal glitches whenever i selected qubes like a staticky tv screen. Qubes release 4.1, latest i3 and i3 tools as outlined in the documentation. T450s. Now this problem.occurs in my xfce+i3 setup.