Why Android hardware-back-button closes Ionic base page (tab controller) when pressed on parent-page?

I’m working with Ionic 3 CLI.

I’ve found some answers for older Ionic environments but I don’t understand how to transform old code for Ionic3 framework.

Android hardware back-button works nice in most situations - but when pressed on the parent page (init page) it closes/hides the app (as it is supposed to do) but it also seems to “close the app” - which causes app to load the whole system again when opened again.

If I hide the app by pressing home-button or open another app by pressing switch-app-button and then open my Ionic app again it opens immediately - but if my app is closed with back-button it will show Splash Screen again and loads the whole app again.

Is there any solution to modify hw-back-button action only to hide the app and not to close the tab-navigation-base-page?

What were the old solutions you found and couldn’t adapt?