The only workaround I found is to first disable your built-in display, then start London Control. It will now correctly find and resize to the remaining display. It's a hassle but it does work. After completing the session, re-enable your built-in display.
An alternative way to achieve the same is to first disable the built-in display, do NOT click on the Windows dialog that asks you whether this is ok or you want to revert, start London Control, THEN click on Revert. It's crude but less hassle and you now have your built-in screen available during the LC session as well (even for Help).
Hoppie
