tag search-as-you-type and autocomplete not only from the beginning

It would be _very_ useful if search-as-you-type and autocomplete worked not only for tags from the beginning, but also for parts of tags.
E.g. it would prevent to have to implement rigid naming conventions for different tags (and remembering them always, e.g. #profession_firstname_lastname or #lastname_firstname_profession or #firstname_lastname_profession etc. or #project_theme or  #theme_project etc.) (apart from it is not always reasonable to have to use the same rigid scheme for everything).