I know this isn't an earth-shaking issue - but I want to know why....
If I want to put a degree sign in a post I type & deg ; (without the spaces)
In the preview box it doesn't work, it shows exactly what I typed & if I press post it stays that way.
But, in the message box, it does change to the little superscript circle, and if I highlight it & copy & paste it in exactly the same place, then it works, it shows up properly in the preview box and in the post.
It's weird.