| Apps still run in the background after I touch the Trash can icon on the Recent tasks screen on my HUAWEI phone |
After the user touches the Trash can 
icon on the Recent tasks screen, some apps (such as the music app) still run in the background. The possible causes are as follows:
The app is locked
If 
is displayed over the upper right corner of the app preview card on the Recent tasks screen, it indicates that the app is locked. You can swipe down on the app preview card to unlock the app, or swipe up on the card to close the app.
Run in background is enabled
When Run in background is enabled for an app, the app will not be closed even if you touch the trash can or swipe up on the card. You can go to Settings > Apps & services > App launch, find the app, touch the switch next to the app to go to the Manage manually screen, and disable Run in background.
Specs design for music, video, and navigation apps
When these apps are playing videos or music or are navigating, touching the Trash can icon will not stop the apps from running in the background, to prevent your music, video, and navigation from being interrupted. The system is designed as so and this does not indicate any issue with your device. You can close these apps on the Recent tasks screen.