I was checking to confirm that the lingering popup in BUG: Another repeatable case of popups that don't go away truly had gone away in 5.0b when I found another one instead:
1) Opened BWS, which opened 'empty' but with λογος already in the reference box.
2) Hit Enter to execute.
3) Along with the results I also got a dropdown below the box:

Now, why would I need a dropdown after I just executed the BWS? Enter should close the dropdown, not open it.