I know it might look like a silly question but here is my case :
My app displays detailed overlay over Google Maps. A very simple exemple with this screenshot (The map will be more detailed when the app’s released):

I’ve noticed that these overlays stay on the view even when there is no connectivity (which is nice):

My question is, is it possible to change the gray grid background displayed in offline mode?
As pointed out by Mimminito and zapl, it is currently not possible to do that.