Form api

We all know that Drupal provides the FormAPI, in which very powerful form elements exist (in our case, the tableselect element). This magical element behaves like a table, but has a checkbox for each line, and associated JS/CSS to handle checking rows. But it is normally impossible to add additional form elements on each row ( there have been many workarounds, but all seem hackish) due to the way Drupal handles form submission. This is how to have a clean (and simple!) way to go around those restrictions.

You've created a form through the forms API, and because you want some custom behavior, you need it to post back to you... so why does you get a 302 redirect when trying to process it?!