Modify form elements based on current select box value in same form? I'm writing a custom module and I have a select box in a form with two values, Test and Production.  I want to remove a specific fieldset from the form if Production is selected, and add it back if Test is selected.  Is there a straightforward way of doing this?
Certainly, you can utilize the #states setting.  Information can be found in the Drupal Forms API as well as in the drupal_process_states() API where you can see examples and documentation on how you can toggle your fieldset based upon the value of that select box.