Drupal.wysiwyg.activeId should default to first editor, not last

Right now Drupal.wysiwyg.activeId is set as each editor is instantiated. This has the problem that it defaults to the last editor on the page to be the "active" one when the page is loaded. When other modules are inserting content into the WYSIWYG, it would make sense for the first editor on the page to be the active one by default.