Check your poison resistance, it'll be 80%. That's the current in-game elemental resistance cap. Nothing to do with this tool, it's a bug from this afternoon's version update. Give it a few days and Larian'll hotfix it back (unless the 80% thing is a stealth gameplay strategy nerf not noted in the changelog).
Oh, ok cool.
Still, I can't use the editor anyway. I load a save, then when I try to click on one of the character tabs, it crashes. Tried different saves as well.