Single Bulk Operation on several blocks I would like to display on a single page several blocks generated by views and associate the same bulk operation to all of them so that the user only needs to click execute once.

Where would you start to achieve this ?

All ideas welcome.
If you have a specific list of blocks you want to alter, get their deltas and invoke hook_block_view_alter in a custom module, as follows:

function YOURMODULE_block_view_alter(&amp;$data, $block) {
  switch($block-&gt;delta) {
     case 'delta1':
     ...
     case 'deltaN':
       // alter the block in the required way by modifying the $data array
       break;
  }
 }


If you want to alter ALL blocks created by a particular module, say, views, do a switch on $block-&gt;module, instead, i.e.:

function YOURMODULE_block_view_alter(&amp;$data, $block) {
      switch($block-&gt;module) {
         case 'views':
         case 'SomeOtherModule':
           // alter the block in the required way by modifying the $data array
           break;
      }
}


Bear in mind that hook_block_view_alter is called for ALL blocks, so if your site has lots of blocks, this may be a performance hit.