Making tables sortable

The sorting feature introduced by CONF-2493 seems to lack an option to enable sorting for "head-less" tables.

Create a headless table:

1. create table e.g. by using the menu
2. delete first row

=> The table is no longer sortable

Workarround to restore the abilitiy to sort content (without using source editor):

1. create new table with same number of columns
2. cut first row
3. paste as first row of table you want to be able to order

Expected behavior:
Highlighting the first row of a table turns the cells into th-elements therby making the table orderable.