ColReorder.js and Fixed Header: dragged header is behind the fixed header, preset columns order

Hello, I'm using the great ColReorder.js extra plugin and noticed that, if I drag a columns header the dragged header shows up behind the fixed header. How can I give it the proper z-index?
The other Question is, I have to hide colum 4 and reorder column 9 instead as column 4. Can I configure dataTables to load the page with this default column order and offer the draggable columns too?

TIA

floogy