For a long time now in Lightroom, there has been a bug where the Secondary Display window resets to the center when switching modes (such as going to Develop and Fullscreen). This is incredibly annoying, and makes it frustrating to use the Secondary Display at all. Please fix this!!
I agree! This is particularly annoying when the secondary display takes over the main screen upon importing new photos; the incoming photos are hidden behind the newly moved secondary display. A series of Shift-Command-Fs is needed to shove the secondary display back to its rightful place. Grrrr!