This could be a problem with JavaScript that runs on those pages that isn't compatible with the current release.

Does that only happen on pages that use a specific editor or does this happen in a normal text area like this forum uses?

This forum seems to be fine.

I see it the most on the Apple and Spiceworks forums.

It seems to reset the cursor to the beginning of the line on a repeating interval, maybe about every three seconds...

This problem is still happening 2 me. It's very annoying n troublesome because it makes u question d security of d browsers. We run many 3rd party applications in order 2 run FIREFOX n if it wasn't 4 them we would feel naked during our Internet activity.

It's so sad 2 c that instead of progressing as human race we get 2 b set back with things like this. At times it makes us just give up d Internet period, we can c now why, Mother hates computers. As it is d alternatives r not good n can't even think about using FIREFOX without those tools. OK66M*COM