This is as much of a discussion than a specific request.

Previously requested here, (separate with ; ), here (for Subsonic, also separates with ; ), and here (general discussion).

Foobar & some others support using ; to separate within field.

OneTagger supports it but uses subgenres - I'm not fully sure how, though one option is by using a custom separate field; more info here.

Beets has canonical nested genres which is pretty cool.

Already in Strawberry if you tag a track with multiple genres split by ; e.g. "Microhouse;ClownPenis", that track will appear in a search for genre:microhouse and also genre:clownpenis, so that's great already. Similarly smart playlists work for "genre contains" any of multiple semicolon-separated terms.

A downside is that if you group your collection by genre, the full term is shown, not both separate terms, which will cause the genres grouping to become nightmarishly messy.

So I think feature request 1 is to allow Collection views which contain Genre to split tracks by semicolon and display the same track under both (or more) genre dropdowns.

Keen for your thoughts. Cheers!

1. Find an album name with a hyphen/dash in it, e.g. "Enter The Wu-Tang (36 Chambers)"
2. Make 2 new playlists with that album in it.
3. From playlist 1, copy that name exactly (I love that you can hit F2 to make editable)
4. In playlist 2, paste that name in the search bar. Nothing is returned until you delete the hyphen/dash.

@jonas any thoughts about this, chap?

Just updated to 1.2.14, no change

rebooted:

locale
LANG=en_GB.UTF-8
LANGUAGE=en_GB:en
LC_CTYPE="en_GB.UTF-8"
LC_NUMERIC=en_GB.UTF-8
LC_TIME=en_GB.UTF-8
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY=en_GB.UTF-8
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER=en_GB.UTF-8
LC_NAME=en_GB.UTF-8
LC_ADDRESS=en_GB.UTF-8
LC_TELEPHONE=en_GB.UTF-8
LC_MEASUREMENT=en_GB.UTF-8
LC_IDENTIFICATION=en_GB.UTF-8
LC_ALL=

No change to those files. The mystery deepens. This is so weird...

@jonas oh weird.

Ubuntu 25.04, language English UK, formats USA but I'll change that to UK. Currently:

locale
LANG=en_GB.UTF-8
LANGUAGE=en_GB:en
LC_CTYPE="en_GB.UTF-8"
LC_NUMERIC=en_US.UTF-8
LC_TIME=en_US.UTF-8
LC_COLLATE="en_GB.UTF-8"
LC_MONETARY=en_US.UTF-8
LC_MESSAGES="en_GB.UTF-8"
LC_PAPER=en_US.UTF-8
LC_NAME=en_US.UTF-8
LC_ADDRESS=en_US.UTF-8
LC_TELEPHONE=en_US.UTF-8
LC_MEASUREMENT=en_US.UTF-8
LC_IDENTIFICATION=en_US.UTF-8
LC_ALL=

I'll reboot for UK and see if it changes anything.

Some diagnosis attempts from Claude, unsuccessful:

All other dates work correctly, including:
2024.10.31 ✓
2024.10.20 ✓
2024.10.10 ✓
2025.07.30 ✓
2025.09.30 ✓
All other October 2024 dates ✓

What This ISN'T:

Integer division (30 // 10 = 3) - would affect 2024.10.31 too
Simple format swap (YYYY.DD.MM) - would affect 2024.10.31, 2024.03.10
All .30 dates - only 2024.10.30 breaks
All month=10 dates - other October 2024 dates work
Hash collision or mathematical artifact
Hex/binary representation quirk

Critical Finding
The sort key starts with 'M'
The grouping header comes from the first character of the sort key. For 2024.10.30 to appear under 'M', its sort key must start with 'M' (not '2' or '0').
Possible Explanations:

Date parsing creates month name string - Parser detects date → converts to "March ..." (month 3) → sort key = "March..." → first char = 'M'
Specific string replacement - Code replaces "2024.10.30" with month name starting with 'M' (March, May, etc.)
Locale-specific format string - Date formatter outputs "M..." format for this specific date only
Sort tag generation bug - Composer field has special date handling that generates month-based sort keys

Theories That Fit
Month 3 (March) Connection:

30 - 27 = 3 → March
Some wrapping/modulo creating month 3 from day 30
But why doesn't 31 also break?

Most Likely:
Specific pattern/regex matching *.10.30 or 2024.10.30 that triggers date-to-month-name conversion, outputting something like "March 2024" or "Mar..." as the sort key.
What We Can't Check (Need Codebase Access)

SortText generation for composer field - does it attempt date parsing?
Date-to-string conversion - any code converting dates to month names for sorting?
Sort key logic - what generates the sortable string from composer tag?
Hardcoded patterns - search for "10.30", "2024.10.30", or month name generation
Article/prefix stripping - any "A"/"The" logic that might affect numbers?
Sort tags feature (v1.2.12) - recent addition, potential new bug

Files to Examine

src/collection/collectionmodel.cpp - sorting/grouping/header logic
src/core/song.cpp - SortText generation for composer field
Date parsing utilities
Any locale/format conversion for sorting
Recent commits related to sort tags

@jonas https://drive.google.com/drive/folders/1W4HT_7AmekeCfh6rdav01jfd3Bhx_Ij0?usp=sharing copied them here but I'm >99% sure it's not the files: I personally tagged them with that specific composer string and only that string seems to cause them to be filed under M.

I just did the same for a random song which wasn't tagged with composed, and it then becomes populated under M like the others:

@jonas any ideas about this one boss? Would be nice to get it off my desk. Cheers!

@jonas any thoughts about this one chap? Super weird, I can't conceive what the issue might be, unless "2024.10.30" somehow compiles to the same hex code as M, or some other completely unexpected, arcane, but technically logical reason.

@rik Oh interesting. That definitely looks like it should display. Sorry mate, not sure then

@ruinspc IIRC you fix this on a per-tracks basis by unclicking "compilation" in the track's properties. Or similar option.

@rlkeeney very unlikely mate, but: any chance it's a hardware issue, and it's randomly finding segfaults on the disk? Worth running a chkdisk on it just to rule it out?