Removing a Global Setting
To remove a global setting, go to the Manage Applications page and click the trash can icon located to the left of the setting you want to delete:
When you click the trash can icon, the setting disappears from the screen, and you won’t be presented with any sort of confirmation dialog box. However, to actually delete the setting from the application you must click Save Changes:
If you leave the Edit Settings page without saving your changes, the setting will not be deleted.