Back, Start, & Search Keys: why are they losing their illumination when using apps?

[Windows Central Question]

Back, Start, & Search Keys

My new Lumia 640 LTE purchased from Best Buy seems to have an issue - the back, start and search keys lose their illumination while using apps on the phone - the apps in question was the photos app on the replacement phone and on the original phone it was the xbox video app - to get them to illuminate again I has to access the notification area (and then swipe back up) - I'm not certain, but I don't believe it is an app issue - any thoughts?

 

[libra89]

If I am understanding you correctly, there is a setting that you can turn on to always have them show. I don't recall it exactly but with that, you can swipe up to hide them just for the moment.