`More layouts…` on login screen: ~500 entries, no search — users can't find their layout

On the Linux Mint login screen (slick-greeter), clicking the keyboard icon → More layouts… opens the full XKB layout list with ~500 entries, no search, no filter, no grouping. In practice, users cannot find their layout — they either scroll endlessly or give up.

The list is overwhelming for what should be a trivial action. In 99 % of cases a user only needs one of maybe 10 common layouts (de, us, us-intl, fr, es, it, gb, ch…). The remaining ~490 entries are noise for the vast majority of users and actively prevent them from finding the one they need.

Steps to reproduce

1. Linux Mint 22.3 Cinnamon, login screen
2. Click the keyboard icon in the top right → More layouts…
3. Observe: a long scrollable list, no search field, entries like:

al plisi - Albanian (Plisi)
am phonetic - Armenian (phonetic)
ara azerty - Arabic (AZERTY)
ara buckwalter - Arabic (Buckwalter)
ara mac - Arabic (Macintosh)
af uz-olpc - Uzbek (Afghanistan, OLPC)
…

Why this matters

The login screen is the worst possible place for a 500-entry list: the #1 reason a user opens this menu is that the wrong layout is active and their password is being typed incorrectly (see Invalid password, please try again in screenshot 1 — exactly this situation). Making them scroll through 500 items under that pressure is UX-hostile.

Every comparable dialog (GNOME, KDE, macOS, Windows) has a live search field for layout selection.

Suggested improvements (any one would help)

1. Live search field above the list, filtering on layout code (de) and display name (German).
2. Short default list of common layouts + an "All layouts…" expander for the rest.
3. Top suggestions based on the system's installed locales.
4. Grouped/collapsible sections by language/region as a fallback.

(1) + (2) combined would be ideal: a small list of ~10 common layouts with a search field, full list behind an expander.

Happy to help test a patch.

Screenshots

(Screenshots will be attached as comments — they show: (1) the login screen with the keyboard menu open and Invalid password, please try again visible, (2) the More layouts… list with no search and ~500 entries, (3) further down the list showing entries like af uz-olpc - Uzbek (Afghanistan, OLPC) that are noise for virtually all users.)

Start at the keyboard icon → More layouts… flow in slick-greeter and reproduce the full-list behavior on Linux Mint 22.3. Review the proposed search, common-layout list, and full-list options before choosing a focused design. Done means users can find a layout without scrolling through the entire list, with the selected behavior tested in the login screen.