Scenes to change only brightness (not power state)

I have run into a problem with scenes (Android App). Scenes always change also the power state of my lights but I would like to change only brightness.

Consider the following scenario: you want to turn on living room lights at sunset (at different brightness so you have to use a scene). Of course you want to change the brightness of all lights so you select every light to be included in your scene but leave them off. One day you’re in bedroom doing something and have lights on. When the sun sets your bedroom lights will go off according to the scene. Not what you want.

TL;DR: LIFX scenes need an option to leave power state unchanged. Or has someone better solution to this?