Keyboard tabbing order issue

Noticing that if you have a tab index in the header cells and the body cells you need to go through the whole table body cells before you are able to navigation to the header cell. https://codesandbox.io/s/react-base-table-forked-ujr0o

Looking through the codebase it seems like this markup order change was related to a styling issue.
" // put header after body and reverse the display order via css // to prevent header's shadow being covered by body"