i happened to activate option kill apps when I leave app.

I want to disable it.

Go to setting> Additional setting>Buttons>Back Select Show recent app tray Now you can check running app by long press on Back button and you can close all running app or can close one one by app.

Left key use also cant close running application you check your setting. Go to setting> Additional setting>Buttons>Recents setting set to show resent apps tray

Answer this question...I can't stop running apps because the left key of my mobile is not working to stop running apps.

When i was clear my caches my mobile switched off my mobile is redmi note prime

xiaomo redmi2-when long pressed middle and left soft key used apps do not appear on screen. how to remove /close the used aps?

Try what Mahantesh has advised....it works

When i press the hold the home button it goes to google

Yes it works, Thanx

press and hold left side soft touch key (out of thee keys) and you can see the running apps and swipe them up..you can see how much memory has become free for use.

press and hold left side soft touch key (out of thee keys) and you can see the running apps and swipe them up

dear press left soft key and hold it to show open apps and then run the cleaner it will automatically shut down the open apps and also clear the cache memory of the phone.

When you press and hold the middle soft touch key, what came out?

it doesnt work when i press the middle soft key to close the apps

Press and hold middle soft touch key (home key). Running apps should show up, swipe them from left to right to close it. Try it and let me know if it works for you. :)