Immersive mode shows a confirmation dialog that shows up the first time the app uses immersive mode. It then adds the app ID to a list of IDs to remember not to show the dialog box again. If the user turns off and on the device within 5 seconds the device assumes the user is in a “panic” mode where they can't figure out how to get back to the navigation menus so the app ID is removed from the list and the dialog box is shown again. Xposed has a module to disable "panic mode".

• description of the dialog confirmation mode logic with code snippet
• to see the list of apps who have already seen the confirmation from the adb shell: settings get secure immersive_mode_confirmations
• Android AOSP ImmersiveModeConfirmation.java
• Code to Xposed's 'Don't Panic' module to disable panic mode