Hi Christian

I have not yet had chance to implement this feature – as mentioned it only works with archives at the moment – I have just realised though if you are a dev and can do some coding this may already be possible using a filter:

http://www.designsandcode.com/documentation/search-filter-pro/action-filter-reference/#Edit_Query_Arguments

So in there you would manually check to see if the current page/post has a specific category:

https://codex.wordpress.org/Function_Reference/has_category

if(has_category( 'dogs', get_the_ID()))
{

}

And if so, modify the S&F query to only look inside that category

$query_args['category_name'] = "dogs"

So putting it all together:

function update_search_category( $query_args, $sfid ) {
	
	//if search form ID = 225, the do something with this query
	if($sfid==225)
	{
		//here we check to see value is associated with the page
		
		if(has_category( 'dogs', get_the_ID()))
		{
			$query_args['category_name'] = "dogs"
		}
		else if(has_category( 'cats', get_the_ID()))
		{
			$query_args['category_name'] = "cats"
		}
		else if(has_category( 'snakes', get_the_ID()))
		{
			$query_args['category_name'] = "snakes"
		}
	}
	
	return $query_args;
}
add_filter( 'sf_edit_query_args', 'update_search_category', 10, 2 );

One big caveat I just realised, you may have to disable ajax – this is because an ajax request gets sent off somewhere else, and I think has_category will never give the correct result in an ajax request.

Thanks