Four buttons lit while charging

[jbryant789]

My kids all have Optimus S phones. Tonight I noticed that one of the phones will have the bottom four buttons lit while it is charging. The other phones don't do that though.

I can't find a setting for this anywhere on the phone, but I'm sure I am oberlooking something..

Any ideas or instruction? And by the way, none of the phones are rooted.

Thanks!

 

[checkers]

I think they light up if the phone is off