Multiple value capability as well as numeric capability have already been requested for Custom fields.

Thanks Lowlander. Would giving the same ability to the custom fields be a feature request?

I can reproduce: http://www.ventismedia.com/mantis/view.php?id=12807

Doing a pre-post search found this nicely relevant topic (and recent too!).

I was going to ask why the custom fields allow multiple entries but display them as separates. Then I saw your comment about the Quality field (which I use a LOT replacing the usual values with things like "Compilation," "Reissue," "Best Of," etc.) and confirmed that mine is also show multiple entries incorrectly.

Hopefully when they fix the Quality field they can do the same for the custom fields too!

I'm also using the classification fields (tempo, mood, occasion, quality) instead of custom fields because of the multiple values support. But it now looks like "quality" has lost its multi value support. I know for sure it worked before. Tempo, mood and occasion still works, though. Is this a bug?

BTW: This works, BUT
The Genre panel (at the top) displays "cleanly" .. items separated by my ";" separator,
but in the Quality panel, you see the full entry, with semi-colons.
I don't know if there's a way to clean that up.

I'm using the Grouping field for a master Genre field.
So, I have only 50 or so major types (Rock/Country/etc.) in Grouping.
Then, I can select Country, and the Genre will show the proper subsets.
-------------------
In the second stage, I'm copying Genre to Quality.
Then, I can do a sub-select of genres.
For example,
..Grouping=Country
..Genre=Southern;1960s
..Genre=Southern;1970s
..Quality=1960s
would be a nice tiering.

Custom fields are not multi-value fields.

I was just working on the same thing ...
I copied Genre to Custom5 (using RegExp), BUT the two tables looked different.
Genre continue to split; Custom5 showed "x1;x2" as a discrete entry.
Is there a setting, maybe, to enable this?

Thank you sir!!

Tempo, Mood, Occasion & Quality all support multiple values (as do the "People Related" fields, but wouldn't make much sense putting Genre information here). If you were to use the Magic Nodes script, then you could create tree nodes for other fields (such as the Custom fields) which will split the values. However, it's more advisable to use a native multi-value field (both for performance, as well as mutli-value support in other areas of the program such as Search).

Is there another field in MM besides the Genre field that supports multiple entries separated by a separator such as ";"? For example, because Sonos does not support multiple genres (such as West Africa; Nigerian; Highlife), I'd like to move all of my multiple-genre tags out of the Genre field (by using the “RegExp Find and Replace” tool), and then re-populate the genre field with only one genre per track.
By moving the existing multiple genre tags into some other field, I won't lose them, (so I can reinstate them when Sonos adds the capability to read multiple-genres).

My hope is to move the multiple-genre tags into some other field that supports multiple entries so that I can still use the functionality in MM.

Does that make senses?

Thanks for any suggestions!