Fix #8819 sorting

@PVince81 Took me a while cause I had a lot to learn, better have a good look :)
I find it a bit strange to have the small point of the triangle pointing upwards when the biggest files are on top, however you see both being used so I left them like they were.

Comments are welcome.

I tried a different approach earlier but decided against it, so it's not needed anymore, I'll remove it.