The captivate will automatically do that after about 2.5 sec from your last touch. I guess it to help save battery or you let you know that the back light is about to go off. as mine typicality the home key s go off the the screen dims the the back light goes off .

I have an issue with my Samsung Galaxy S Captivate.

The lights for my Home key buttons on the bottom of the phone keep turning off before my back lights turn off.

Is the phone just like this, or is there a way to change this? I've tried looking every in the settings and there is nothing about incoherent lighting for the home keys.