Why JS doesn't work on a saved page? I've tried to save /admin/structure/block page and open it with Firefox 14.0.1. After this I cannot drag blocks. Why is that? There are no errors in the console. How should I debug such behavior? I need this to better understand why doesn't Drupal work for JS-loaded content. The symptoms look similar.
The Drupal's jquery.once.js is to blame. Deleting every *-processed class worked.