Q: Why can't I see the whole inside of the factory building in the preview window?
E: You're using a reduced GUI scale. Currently camera GUI components don't scale with the GUI, so you'll have to go into the mod options (Options -> Mods -> Per player) and adjust the preview zoom setting. Unfortunately I can't detect your GUI scale myself, otherwise I'd have used that.
http://lua-api.factorio.com/latest/LuaPlayer.html#LuaPlayer.display_scale is a thing in 0.16 which should fix the known issue at the top of your mod portal page.