Option to move buttons into collapsible fieldset

I wanted to put the entire exposed filter form (fields and buttons) inside a collapsible fieldset. Using the current 'secondary form' method only moves the fields and leaves the buttons exposed. It would be nice if there were another option to make the entire form collapsible (keeping the ability to have a secondary fieldset, so you could have a collapsed fieldset inside a collapsed fieldset).

In the mean time, I have achieved this using the code here: http://drupal.org/node/1224284#comment-5869902

On a side note, I tested the ajax functionality with autosubmit (so no buttons). This worked, but each time you updated a filter, the fieldset would collapse.