Please prepend the right-floated sorter icon to the headings instead of appending it. Appending causes the icon to fall to the next line when the <th> element does have white-space: nowrap. I know this is totally counter-intuitive but here's the fiddle:
Its a good point. Can't you just remove the float:right from the sorting icon though?
I'm a little reluctant to do it since it might break backwards compatibility and there might be an acceptable workaround.
If I don't float it to the right then it won't be aligned to the right :)
I moved it from :after to :before for my app and with a bit of CSS tweaking it looks OK.