If you add a document using either UCM web console (http://ServerAddress:16200/cs), or the RIDC API, and you specify a TAG value, this tag is not recognized by Webcenter.
If you follow this link, you will see four screenshots.
Adding the document, giving it the title "Bench" and the tag "park".
The result of the search query with the keyword "park" in WebCenter spaces environment.
The result of the search query with the keyword "Bench", which is the title of my document. This one is clearly showing that the tag is "park"
The WebCenter detailed view of my document, showing no tag is associated with my document, even though it showed the tag before I clicked on the document for a detailed view.
One thing to note is that if I wanted to tag a document using Webcenter Spaces, it would be recognized everywhere this way. It is not convenient if someone wants to add document programmatically (RIDC) of by the UCM Console.
If someone have any idea how to fix that, I would appreciate a lot your help.