Add a domain filter to the transation overview page

Are you familiar with the module_exists() function? it would simplify this patch a bit. Also you're not following the Drupal coding standards for spacing between the if and ( and ) and {. Take a look at the coder module to help identify these issues.

+  //The domains filter
+  if (($file = db_result(db_query("SELECT filename FROM {system} WHERE type = 'module' AND name = 'domain' AND status = 1"))) && file_exists($file)) {
+    $domains = domain_domains();
+    if(count($domains) > 1){
+      $filters['domain'] = array('title' => t('Domain'),'options' => array());
+      foreach($domains as $domain){
+        $filters['domain']['options'][$domain['domain_id']] = $domain['sitename'];
+      }
+    }
+  }

Could you put a comment that domain referes to the domain access module? Actually could you do that on the other part too?

+        case 'domain':
+          $table = "da$index";
+          $where['domain'] = "$table.gid = '%d'";
+          $join[$table] = "INNER JOIN {domain_access} $table ON n.nid = $table.nid ";
+          break;

I'm not persuaded by your argument against using module_exists(). The results are statically cached so it only happens once per request and there's plenty of other places in the code where it's called. We're already calling language_list() which indirectly calls module_exists().

thanks, committed to HEAD.