When you close an app with the Home button, it continues to run in the background and still requires memory, which other apps might lack.
Therefore, it is highly recommended, especially before performances, to completely close all these apps, including SongBook+, and then restart only SongBook+ to make as much free memory as possible available for this app.
Double-click the "Home" button on your iPad. For an iPad or iPhone without a "Home" button, swipe up from the bottom of the screen, stop briefly in the middle, and then release.\
SongBook+ also has a menu item "Close SongBook+" on the "..." button, which can be used to completely close it.
Swipe the app you want to close up off the screen.
If you can't see the app you want to close, you can scroll until the desired app is visible.
