Because Pokemon Go has a bug on the iPad version and I cannot see the number of Pokeballs remaining to catch a Raid Boss (due to aspect ratio of iPad about 4:3, not the same as iPhone's 16:9), so I want to use the 2-app-side-by-side method to see if I can somehow change the aspect ratio of the app.
So I either run Pokemon Go and slide in a Safari, or run the Safari and slide in Pokemon Go. (By running Pokemon Go, and then slide from bottom up of the screen to see the dock, and then touch-and-hold an app and move it to the edge of the main screen area).
Either case, I see Pokemon Go running as a full screen app. Is it true? Some apps cannot run as a side-by-side app but must remain full screen?