Steps To Reproduce:
(1) dock pixelbook to another monitor
(2) set it up as an extended screen (dual screen set-up_
(3) Convert pixel book to tent mode


Expected Result:
use pixelbook as a second screen in tent mode with extend display setting 

Actual Result:
screen set-up will automatically change to "mirror" with no way to change it back to extend

How frequently does this problem reproduce? (Always, sometimes, hard to
reproduce?)
Always