World Composition Mini Map updates

I created a World Composition in World Machine and exported it to Unreal and everything went fine, I did the maths, so I have my level tiling properly inside the engine. My doubt is…

How do I update my World Composition Map? I would like to leave all the levels unloaded but it would be nice if I could have the entire map in the world composition. Right now what i get is just one tiny piece of landscape visible and the rest of them show completely white when loaded. How can i make the entire map visible ?