Custom Field Order in Field management area

I need to order my custom fields so the fields flow in a sensible fashion. For some reason I am unable to change any of the field orders. I've tried to type in numbers (I can't type any in) and I've tried the small arrows (they are not allowing me to click on them).

Is there a setting I am missing? It was seem like an easy thing to do (just like the Joomla! ordering method) but I'm not able to make it work.

Hi

Please click on header of order column. After that, you will be able to change order of these custom fields.

Regards,

Tuan