Alex, I was editing a lesson in single pane view. I highlighted a new word to make it a LingQ, the definition box pops up as expected, I pick the definition I want, and then I am unable to close the box by clicking the “X”. There are numerous workarounds in the screen to get the box to close, but you might want to fix this if you can reproduce it. I enclose a movie of me doing it.
Regards,
Jack