PSA/ee/docs/plans/2026-03-09-ticket-comment-order-browser-preference/PRD.md

PRD — Ticket comment order browser preference

• Slug: ticket-comment-order-browser-preference
• Date: 2026-03-09
• Status: Implemented

Summary

Persist each browser's ticket conversation comment-order choice so users do not need to re-select newest-first or oldest-first on each ticket view.

Problem

TicketConversation currently resets comment ordering based on the incoming defaultNewestFirst prop each time the component mounts. Users can flip the order within a ticket, but that choice is not remembered for later tickets in the same browser session or future visits.

Goals

• Remember the user's ticket comment order choice per browser.
• Keep defaultNewestFirst as the fallback when the browser has no saved preference yet.
• Update the saved preference silently whenever the user changes the order toggle.

Non-goals

• Cross-browser or cross-device sync.
• New backend APIs, database changes, or server-side preference persistence.
• Any UI changes beyond keeping the existing toggle behavior and labels.

Users and Primary Flows

• MSP ticket users open a ticket conversation and see comments in their preferred order if they have chosen one before in this browser.
• A first-time user with no saved browser preference continues to see the order implied by defaultNewestFirst.
• When a user flips the existing newest/oldest order control, subsequent ticket conversations in the same browser use the new choice automatically.

UX / UI Notes

• Reuse the existing order toggle in packages/tickets/src/components/ticket/TicketConversation.tsx.
• Do not add confirmation, toast, or settings UI for this preference.
• The behavior should feel silent and immediate.

Requirements

Functional Requirements

• On initial render, TicketConversation must check for a stored browser preference for comment order.
• If a stored browser preference exists, it must override defaultNewestFirst.
• If no stored browser preference exists, the component must initialize from defaultNewestFirst.
• When the user toggles the comment order, the component must update both the rendered order and the stored browser preference.
• The same stored preference must apply to standard conversation comments and external comments because both are driven by the same order control.

Non-functional Requirements

• Storage access must be safe in environments where window or localStorage is unavailable.
• Invalid stored values must not break rendering and should fall back to defaultNewestFirst.
• The change should remain isolated to ticket conversation UI code and avoid unnecessary rerenders or backend dependencies.

Data / API / Integrations

• Use browser localStorage only.
• No server actions or API routes are required.

Security / Permissions

• No permission changes.
• Only a non-sensitive boolean UI preference is stored in the browser.

Observability

• No new telemetry or logging is required.

Rollout / Migration

• No migration is required.
• Existing users without a stored browser value continue to use defaultNewestFirst until they change the toggle.

Open Questions

• None.

Acceptance Criteria (Definition of Done)

• A user with no stored browser preference sees comment order based on defaultNewestFirst.
• A stored browser preference overrides defaultNewestFirst on subsequent renders.
• Changing the newest/oldest toggle updates the stored browser preference silently.
• Automated tests cover fallback behavior, stored override behavior, and persistence on toggle.