This entire commit should be made backwards compatible as in my previous post [del] (or a comment added that it is for PHP v5.6+ only)[/del] as the current PHP versions that FA supports cannot handle the new constructs effectively. There are no $_GET variables available when the new set_posts() function is called in this way as the session.inc erases all $_GET values except for those coming in thru Ajax - js http requests. The set_posts() however acquires the ajaxed GET variables correctly.
The persistence of the history works on substitution of ...$vars with $vars and changing to get_js_history(array(......)). [del]The ChangeVar of the combo boxes do not work even with the set_posts(array(......)) fix[/del].
For those wishing to test it further, the attachment would be useful. It contains the BraathWaate files with the existing counterparts in the core and the altered ones to incorporate this commit into the inquiry files with the backwards compatibility fix for the new functions.