LG G3 knock on/off function not working..how to recover?

[feilila]

I don't know what I did to my phone, but I can't double click to lock the screen now.

However, I can still unlock the screen by double click..

What can I do to recover the function?

***Edited to add labels***

[feilila]

thanks a lot! it works

[Automagic]

Fill* not film.

[Automagic · Accepted solution]

To lock the screen by double on the G3 you need to double tap on an empty portion of the screen. Did you film your home screen with apps or widgets?

You can also double tap the notification bar at the top of the screen to lock.