edge notification only appears 1 second - How to make it stay?

[Android Central Question]

I receive a whatsapp message, edge notification does 1 round of the screen and then stays black. I want my notification to stay until I unlock the phone. Is this possible??

Not sure what the point of edge notification is if it only shows you notifications when the message comes.

 

[chanchan05]

The point of the edge notification is when the phone is facedown, the edge lights up the area around the phone. There were demos of this when this feature was first launched on the S7 and S6. They just added more features to it and made it look prettier. It was never meant to be a replacement for a notification LED.