Make ctrl+arrow keys move the text cursor a word instead of line in forums

I know this is a tiny thing but in the main post box in the forums pressing CTRL + an arrow key moves the text cursor to the start or end of the line instead of jumping a word as is standard. Just an annoyance when you're used to every other field for entering text behaving differently.
Not sure if exclusive to Firefox 54.0.1 which I'm using or anything but it works as usual in the box for entering post title for instance.
Also not sure if its the correct place to post this but couldn't find one that seemed more appropriate.