i have a map with biter base set to player owned but the biters do not expand. why the enemy biter expand but mine wont ?

i can build offshore pumps outside of map borders on map with limited size. i played factorio version 0.15.2

oil patches are so damn hard to see in map editor without minimap. is there any mods or console command to make oil patches easier to spot in map editor?

im new to this game. theres some question i wanna ask

in sandbox scenario with infinite size, the areas that havent been discovered yet are automatically generated once you scroll to that area, right?

usually when i start sandbox game i see there are no enemies within the player's starting point ...