@Orca That would make sense, with "hatter" as a verb turned into a noun, describing a profession in which one makes and provides hats. Also apparently, some of the materials in hat making were toxic and effected people's cognitive well being, from what I recall reading? Hence, mad hatter.
@timberwraith Though yeah, I always disable every visible spell checker settings first time I set up a computer. They're never useful and only serves to pollute my visual capability with full sentences of red underline.