Question

My the_content filter kills gallery shortcode and I dont know where the problem is…
I can add just blank the_content filter and gallery disappear from the content and there is just text. I am using the_content filter:

function test($data){
    echo $data;
}
add_filter('the_content', 'test');

Any suggestion how to fix it?

Answer 1

This is a common mistake, you just need to return the information to keep applying new filters, so change the function tho this:

function test($data){
    //apply here any content modification then return new content
    return $data;
}
add_filter('the_content', 'test');

You can get more information at: http://codex.wordpress.org/Plugin_API/Filter_Reference/the_content