SCREEN PINNING FEATURE OVERVIEW
Pin-shaped icon signification on Recent Apps screen
When you clear apps in the Recent Apps list, pinned apps won’t be removed. Tap the
pin-shaped icon to keep apps in the Recent Apps list.
How to use
1. When an app is pinned, it will not be removed with Clear All, swiping or delete ( X ) button.
2. Dual window, Pin and Close buttons may appear slower when you open Recent Apps.
Please be assured it is a sign of normal operation on Android OS.
3. Use Clear All to remove apps (except pinned ones) to clear some memory space.