I am making my iPhone app to support iPad .
But after running in Xcode 's iPad simulator , I found that the Multitasking Controls button (three dot button) is missing in my app's statue bar ,

but exist in other apps (eg : Files app)

Is there any develop configuration for this button 's hide&show in specific app
I have remove UIRequiresFullScreen key in the info.plist already . any other option to toggle this button ?