Broken area of map

I am currently have a strange issue with the terrain editor. There is a fairly large portion of the map I am not able to edit in anyway. I can’t even move my brush over the area as if there is an invisible wall all around it blocking access.

If that terrain is on another submap then you need to make that level the main working level and double click the terrain

No it’s all one map.

Can you post a screenshot please?

Also, you may want to reconsider having all your terrain on one map like that. It may result in some severe FPS drops. Usually a good rule of thumb is to use smaller sub sections to make up a bigger piece of land, that way, if the player is not in streaming distance of it, it doesn’t get rendered (you can always set the streaming distance up via layers in the World Composition tool). But it all really depends on what you are going for I suppose and personal preference, just bear in mind the possibility of FPS issues and be sure to test.

One last thing; How big is your terrain?

I changed the section size of the map and that seemed to fix the problem. The entire map is 1250 x 1250. Do you think that would cause FPS issues? If so is there a way to section off what I already have completed instead of reworking it all?