Somewhere Between Firefox and Facebook

Somewhere Between Firefox and Facebook
What this is in relation to is, Spell-check.
I have been running into this issue since firefox 3.
I’m on Facebook, I’m typing a message, staring at my fingers because I can’t type. I look up and see a mess load of error in my spelling. Everything is underlined in squiggly red, so I right click each spelling error, select the word that is the proper spelling of my typo. Correct all of my spelling errors. I press send. Look back up at the post, and all of the errors are back.
What?
Why?
Why does this happen? what is causing all of my typos to reappear?
I have found one way around the issue is after I type my message and fix the spelling errors is if I put a smiley face or a frowny face or what ever is closest to the mood of the post, emote after the post, the issue is does not came up.
Firefox, you need to kick facebook in the crotch for us, or facebook, kick firefox in the crotch, or both commence to sac kicking.

firefox and facebook do not agree on the spell check feature that firefox has? Or does firefox just want to prove that all facebook users are idiot? Does facebook want to prove that all firefox users are idiot?
I know this issue happens on the work computer, the home computer and the laptop.
FIX YOUR FREAKING SPELL CHECK!