1.6 beta Dell d3100 / m1 MBP broke external
 

Hello,
after installing the 1.6 beta, my external displays (two 1920x1080 hdmi monitors connected via HDMI ports on d3100 dock) no longer work. One of the two monitors appears in the apple system preferences, and powers on. I cannot drag windows, or even a mouse cursor onto external monitor 1. External monitor 2 doesn't show up in system preferences. I uninstalled and reverted back to built 1.5 and now everything is working as intended. Any ideas?