Currently, some blocks related to advanced features can be added, even if this feature is disabled (for instance, blogs).

A mechanism should be added to hide the block from the "Add a block" list if the main feature they are using is disabled.

This is the list of blocks that could take advantage of this:

• Accessibility review ($CFG->enableaccessibilitytools)
• Blog menu (CFG->enableblogs)
• Blog tags (CFG->enableblogs + $CFG->usetags)
• Recent blog entries (CFG->enableblogs)
• Comments ($CFG->usecomments)
• Course completion status ($CFG->enablecompletion)
• Flickr ($CFG>usetags) --> No change is required because it can be only added in tag pages (which can be accessed only when tags are enabled).
• Global search ($CFG->enableglobalsearch)
• Latest badges ($CFG->enablebadges)
• Learning plans ($CFG->core_competency | enabled)
• Tags ($CFG->usetags)
• Random glossary entry (mod_glossary)
• Network servers (auth_mnet)