Yeah Bill,
You're exactly right.
It's amazing that your spell-checker, gives that spelling of thier!.
Incidentally, the way I have just spelt thier, is correct, but it doesn't look right!.
Another word that constantly trips me up is recieve, following the rules of grammar, it would be spelt recieve.
Being a Radio Ham, this a word I type quite frequently.
It's really strange, eh?. [Linked Image]