If the sidebar, widgets, admin bars or any other items in the WordPress admin menu is not loading in your WP install when compared to some another, then here is the fix:
- Edit your wp-config.php found in the root directory of your WordPress installation.
- Add the following line just before the closing of wp-config.php
- Save the changes
- Logout and Login again to the WordPress admin
The problem will be fixed by now 🙂
More info: zend.ze1_compatibility_mode