Select

Divergences, open decisions, and undocumented gaps for Select.

See Select for the decided part of this page.

Known issues

ID	Kind	What
TITAN-DIV-24	Divergence	The trigger’s error focus ring is a third red, unaliased to the semantic error tokens — inherited from the field chrome it shares with Input
—	Needs sign-off	This page previously pointed to a separate, undocumented “Combobox” for typing to filter options — that was wrong. Autocomplete is modeled as a mode of Select in the design library (an Autocomplete variant, false/true, on the same Select Input component as everything else on this page), not a separate component — see Vocabulary. There is no Combobox page or component anywhere in the library’s 49 pages. Titan’s actual code structure for this is unconfirmed without a checkout.

Gaps in the current rules

• No decided behavior for zero available options.
• No truncation rule for a long option label, in either the trigger or the list.
• No decided threshold for turning Autocomplete on — the design library shows it as a binary mode, not a rule tied to option count.
• Multi-select’s trigger summary format is undecided — a count, chips, and a truncated label list all satisfy TITAN-SELECT-05 without choosing between them.
• Whether the option-list overlay shares implementation with Menu — the shared naming is suggestive, not confirmed against source.

Constraints Titan should enforce

These are real, currently-true rules. Nothing in code stops a builder from violating them today — each is a placeholder for a guardrail Titan hasn’t built, not a decision still being made.

ID	Constraint	Would be enforced by
TITAN-SELECT-03	The placeholder is never itself a selectable option.	A lint/runtime check comparing the placeholder text to the option set.
TITAN-SELECT-04	Option group headers are not selectable.	A test asserting group-header elements fire no selection handler.
TITAN-SELECT-05	A multi-select trigger summarizes rather than growing unbounded.	A built-in default renderValue truncation/summary utility.
TITAN-SELECT-06	A disabled Select is paired with a reachable explanation.	A required-when-disabled explanation prop.
TITAN-SELECT-08	Sub-options nest exactly one level, never deeper (needs confirmation).	A recursive type disallowing a third nesting level.