I was using the "customize" option for a theme and i noticed that when you save to the entire site, you loose any changes made for separate pages...sounds like it's doing it's job, doesn't it ?
But it's a pain when you wipe out all your different page setups.

I have added a .less entry for page background images. So i can give every page a different background. Works really nice. But if i want to change any other style, like change the size of <h1>. I'll now have to change it on every page, or loose the images.

It would be great when you could select which style items to save site-wide, or only save the changed or edited items, and leave the rest as they were.