Re: planet is surrounded by spy satellites
"OT: Oi, El Reg! The wavy red line of disapproval appears beneath the word when I write kilometer, but disappears if I swap the last two letters. Please load a proper English dictionary! (Or in this particular case, a French one, I guess)."
Assuming you're not actually joking:
(a) The dictionary is supplied by you via your browser. In my case, using Seamonkey which is the same program for both browser and mail, I get exactly the same underlining in both the browser and the mail composing windows.
(b) Kilometre is the original French spelling and hence is correct unless you live in a country that also thinks that colour and theatre are also incorrect.
If you wish to persist in using the spellings currently in vogue in the colonies load the en_us dictionary or right-click on the word and add your misspelling to your dictionary.