Steps to reproduce the issue

I tried to create two selects for the ordering of the backend lists instead of the single one, one for the field (eg title, autor, date, ...) and one for the direction (ascending, descending).
Reason is that I think when we have many sorting options, the "fullordering" select (eg title ascending, title descending, autor ascending, autor descending, ...) gets out of hand. In case of com_content we get a select with 24 options. Using a splitted select we could cut the options in half, making choosing the right option easier and also reducing the work for translators.

Expected result

Able to do that using the filter_xyz:xml by specifying the ordering and direction field instead of a fullordering field.

Actual result

• I can select a different column ordering using the dropdown, however changing the direction doesn't have any effect.
• Changing the ordering using the table headers works fine, but the dropdowns don't reflect the changed ordering. It says on the last selected value.

System information (as much as possible)

Not relevant

Additional comments

I think this happens because the JS involved with SearchTools (https://github.com/joomla/joomla-cms/blob/staging/media/jui/js/jquery.searchtools.js) is always using the full ordering (eg "title asc") in one field. While we can change the name of the field it uses, we can't change the behaviour to populate two instead of one field.
It would be great if we could change that behaviour using an option that we pass to the searchtools JLayout (https://github.com/joomla/joomla-cms/blob/staging/layouts/joomla/searchtools/default.php).