\tag and \tweak

[Werner LEMBERG]

This time a syntax question: Is it possible to combine `\tag` with
`\tweak`?  I have tried the following:

  g-\tag #'score \tweak X-offset #-3
                 _\markup { "foo" } |

However, this makes the `\markup` disappear if `\keepWithTag` doesn't
contain `#'score` (which is kind-of logical).

In case there isn't a nifty trick I will prepare a patch for NR to
explicitly state that `\tag` doesn't work with `\tweak`.


    Werner