Cocoa, Objective-C, macOS : How do I program UI showing a specific NSButton/popup under "Spotlight" effect in XIB file, macOS application

I am seeking for this User Interface(UI) effect --> "Spotlight" a specific IBOutlet (Please see attached Image2.png below) for a week!

Explain the "Spotlight" effect : I wish to create is effect similar to NSAlert or beginSheet effect which user cannot click or access the entire window/view until user trigger a button and it back to normal. The whole window/view will becoming darken or gray EXCEPT a specific button I allow my user to interact with.

Yet, I found that there is no any trick to create such effect neither in XIB file nor objective-c code.

This is urgent for me. Eagerly waiting for your reply. Much Appreciated.

(Image 1.png)

(Image 2.png)