"Black Line" issue

[ZachTheCat]

Well, howdy fellas, I just got warcraft 2 days ago and noticed world editor yesterday. I decided to try making a map to play with my friends (simple 4 ffa map using the same concept as "Borderlands") but, ran into a small snag. Other than known problems with the units, I am talking about the black line that is acting like a "boundry" and trapping the top right player to the south.

Well, my question is this, was it when I adjusted the map size it created this line? If it wasn't then what did and how would I go about removing it?
I added screenshots of the black line below

Things I have tried so far:

1. Color over it with terrain brushes
2. Adjust elevation
3. Add units
4. Add trees
5. delete trees

I also adjusted for shadows.
Thanks!

 

[Dameon]

terraintool remove boundry

 

[ZachTheCat]

terraintool remove boundry

HAHAHAHA Now I feel stupid, thank you sir.