Tags confusing (to all or me only)

Can you guide me how should we force it to search for hashtag (#howto in this case)?

And, if we search for tagg1, does it also search for a msg which has normal tags tagg2-tagg1 or Tagg3 Tagg1 (or or a msg having these hash tags, but different normal tags).

Can you pls tell its current expected behaviour?