After some hours of searching I discovered that there is a lack of Drupal 7 multisite tutorials there was only one article that talks about the new sites.php feature - (there are some more now), but when it comes to simple guides, there's hardly any thing like that.
Usually calling Drupal.attachBehaviors makes the new elements added to the DOM reflect changes that happened to the old elements as desired. This, however, is not always enough. Sometimes, we need more control, it is easy to alter the response if you created the AJAX call yourself (using jQuery $.ajax() for example), but what if you are building on others' work..
Here is our case here :
In Drupal 6, Views Filters can be automatically submitted (without pressing apply button) using a simple JQuery trick like this one (or using Views Hacks module)
$('.views-widget select').change(function() {
$(".view-filters form").submit();
});