Magnetic case cover will not shut off screen

I got a 3rd party case for my Note 4. I am expecting it to turn screen off and on upon opening and closing. Yet, it doesn't. Is there a system setting I need to activate for this to work properly? I am inning Android 5.01

[HELP] LG E975 shut down after bootlogo

my phone LG E975 keep shutting down after the LG animated logo.
Few days ago, I installed brain dots, and keep playing it until my phone got hot and then shut down, but I can turn it back on and everything worked normally, today I played again and my phone got so hot again and shut down.
but now, it always shut down again after the animated LG logo. sometimes I can see my wallpaper before my phone shut down sometimes it shut down in animated LG logo.

my phone is unlocked, rooted and has CWM recovery 4.1.2 Stock ROM

I tried :
- custom restore to restore boot img from my old nandriod backup. still dont work.
- flash custom kernel ( that I have tested it before and work great, Solid Kernel 0.8)
- wipe cache and wipe dalvik, after "starting apps" message then it shut down again.

is there a way to test which app that cause my phone to crash?
a log of what my phone did last time before crash?
If I can, I dont want to flash my phone