Hello Guillermo
Atm, you can edit tags from different places:
1. in the media browser you can right-click on the artist and choose
to change the artist name for all the tracks that are visible with the
current filtering (through the search entry) for the particular artist
2. in the media browser you can right-click on the album and choose to
change the album name for all the tracks that are visible with the
current filtering (through the search entry) for the particular album
3. in the media browser you can right-click on the track and choose to
change the tracks metadata
4. in the track list you can right-click on the track and choose to
change the tracks metadata
So with 1. and 2. you can edit several tags at the same time with
respecting the current filtering through the search. That's the only
'mass' in tag editing.
If one of the mentioned points do not work for you, it's a bug in
xnoise on Archlinux.
Regards