Currently if you add a default value inside a filter using, for example:
public function default()
{
return 2;
}
It will select and apply the filter as expected but it will not provide any visual indication that a filter is currently selected and applied, leading to confusion as to why results are being filtered
IMO, if a filter is being applied, it should always cause the filter button to be highlighted and the number next to it to increment based on the number of filters currently active, whether that filter is a result of a user action or a default value