The quest of the lost $_POST

— I am sorry : yes there are many other posts to treat that problem, but they are closed and none is answered —

I am currently developing a plugin which adds a form in another’s plugin page through actions.

In fact, to be precise, I am adding a form to the current activity form of BuddyPress, but since this problem is not BuddyPress related, I am asking here.

When I submit the form, the $_POST data returned is always empty when I include code into my plugin. What I mean is that my plugin goes like this :

Check if buddypress is loaded
then load form.php

In form.php, there is the mentioned form and its logic of analysing the $_POST when submitted.

I also figured out that when I put the $_POST logic in the main plugin file, I can access the $_POST data, but I can’t use wp_nonce_field to verify the integrity of the data AND the page redirects to the home page of the blog.

What, in the word of WordPress gods, is interfering with normal html/php code so that simple task doesn’t work?