To fix the problem, there should be a "river.pxa" inside the data>stage folder, grab a new copy of Cave Story, find and copy that file, and then in your mod you want to paste and replace the broken one.
ok thanks
i made a copy of my data just in case... ill test that out after
I am using boosters lab but I've actually used 3 different editors for this mod
At the beginning was sues workshop, middle was cave editor (and improved beginning) and so far what I've done now has been boosters lab, and I think I'm going to stick with it unless someone else makes something SUPER DUPER cool
the only thing I ever use cave editor for is changing map sizes
I don't know how to do that in boosters lab..
You can resize maps by right clicking on the map while in tile mode. As for making the arrows be flowing water, check 'show tile types' and see if the arrow tiles in question look like this: https://files.catbox.moe/xb5jp8.png.