The Tag view is available below the Explorer and Filter views.  It provides links to a list of Items that is independent of Sets.

There are two views of the Tags: Cloud and List.  The Cloud view displays the Tags with the font size determined by the number of Items "tagged" – the larger the font, the more Items that have that tag.  In either view, just click on the Tag to view the Items assigned to that Tag.

Search & Filter on Tags

For advanced Tag queries, you can use the search engine or keywords box within Filters.

Use the prefix Tag: to indicate the Tag field in your query.

tag:"requirement management"  AND tag:security

tag:"requirement management"  AND tag:security (tag:"user"  OR  tag:security) AND tag:requirement

 

You can use the plus sign as a shortcut for the AND operator and the minus sign for NOT.

+tag:"requirement management"  -tag:security

test case +tag:requirement   +tag:security