Swift: How to remove default auto first responder assignment

Question

The app automatically assigns the first control in the document outline to the first responder automatically after the app launch (See reset button in the screenshot below).

I did not assign any control to be the first responder in my code. How to disable this behavior using swift?

I have referred and tested some Objective-C methods about resigning first responder but no effect.

Any hint or comment is appreciated and thanks for your time viewing this question.

Answer 1

After a day of investigation, I finally realize that it is my own problem. The button is auto-focused because I turned on the full keyboard access on my Mac (See screenshot below). It behavior commonly after I set it to the Text box and lists only .