Prevent Editor window from opening on launch

In System Preferences I have Keyboard Maestro Engine in the Login Items list. It is not set to hide.

In KM Preferences I have (obviously) checked 'Launch Engine at Login'

So why does the Editor window open up every time I reboot?

This happens on both my MacBook Air and Mac Mini, both with 10.15.5 and now at 10.15.6.

System_Prefs Preferences__General