While labels are provided by Confluence to group pages by an arbitrary sequence of characters, normalized to lower case letters, projectdoc tags allow to do the same but without making the tag names visible to the label system.
So if you want to tag a document publicly, use labels. If you want to add an arbitrary discriminator, only shown on the page, use tags.
Querying documents by labels and tags is supported by the Lucene keyword Tags.
Example Lucene Query on Labels and Tags
Tags = "My Tag" AND Tags = "my-label"
If you need to define a search on Tags (or other properties) having a list of properties as value, then use the list query operator.
Exact match query using OR
$<Tags> ~ (One, Two, Three)
For more information on list queries, please refer to Search Tips.
If you use the Tag List Macro, the Confluence labels are also rendered in the tag row of the document properties table. This allows you to provide a documentation for your Tag.
Flags
Flags are like tags, but without the implicit requirement to document them. Like tags the values of the flags property are used for metadata-tagging.
While tags are typically rendered on the document, flags are not.
Since 2.4.1
Flags are available since version 2.4.1 of the projectdoc Toolbox.
Selectors
In case you do not need to show your labels or use them for meta-tagging, then choose the naming convention "Selector" for adding additional selectors. In case you need multiple sets of selectors, add a suffix to "Selector" like "Selector Security Issues.
While tags are typically rendered on the document, selectors are not.