Add 15 community knowledge articles from BC Code Intel ingest

Ingests net-new /community knowledge from BC Code Intelligence, surviving
the admission test, gray-zone salvage, and dedup against the full corpus.

Domains: ui (6), error-handling (3), performance (2), upgrade (1),
appsource (1), security (1), telemetry (1). The two BC24 No. Series
migration drafts are merged into one article.

Adds good/bad AL samples for the clean-fit articles (error-handling,
performance, security, telemetry). UI and appsource remain knowledge-only.

Validator and knowledge-index checks pass (207 articles).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

community/knowledge/ui/factbox-design.md

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+---
+bc-version: [all]
+domain: ui
+keywords: [factbox, subpagelink, listpart, cardpart, page-part, related-information, flowfield-sift]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Filter ListPart FactBoxes With SubPageLink To The Parent Record
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+A FactBox is a page `part` that surfaces related data beside the main record so users avoid navigating away. Every FactBox runs a database query as its host page loads, so an unfiltered one is a hidden performance tax paid on every page open. The remedial trap: a `ListPart` FactBox with no `SubPageLink` does not show "the related rows" — it loads and pages through the entire source table, because nothing ties it to the host record. This makes correct `SubPageLink` linkage, not visual layout, the load-bearing design decision.
+
+## Best Practice
+Give every `ListPart` FactBox a `SubPageLink` that maps a field on the part's source table to a `field()` of the host record (for example `SubPageLink = "Document No." = field("No.")`), so it returns only rows belonging to the current record. Prefer a `CardPart` when you only need summary figures (balance, availability, status) — it reads a single record and avoids list overhead entirely. When a FactBox shows FlowFields, ensure the calculated total is backed by a SIFT key (`MaintainSIFTIndex`) so the sum is read from the index rather than aggregated row-by-row on each load. Keep FactBox count modest and avoid heavy `OnAfterGetRecord` logic in the part.
+
+## Anti Pattern
+Adding a `ListPart` FactBox without a `SubPageLink`, expecting it to "just show related lines." The consequence is a full-table scan on every page load that grows with the dataset and is felt worst on list pages, where the FactBox re-queries on each row selection. Reviewer signal: any `part(...)` referencing a list-type page part where the `SubPageLink` property is absent, or a FactBox FlowField filtered on non-indexed fields. A second smell is duplicating data already on the page or stacking many FactBoxes, which multiplies queries for little context gain.

community/knowledge/ui/fasttab-field-importance.md

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+---
+bc-version: [all]
+domain: ui
+keywords: [importance, promoted, additional, fasttab, show-more, summary-line, progressive-disclosure, field-visibility]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Set Field Importance To Drive FastTab Progressive Disclosure
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+A FastTab field's `Importance` property controls whether the field is visible immediately, hidden behind "Show more", or surfaced on the collapsed FastTab header summary line. The three values are `Standard` (the default, shown in the expanded FastTab), `Promoted` (also rendered on the FastTab header when the tab is collapsed), and `Additional` (hidden until the user clicks "Show more"). Misusing these values either clutters the summary line or buries fields users need on every transaction, so reviewers should treat `Importance` as a deliberate layout decision rather than an afterthought.
+
+## Best Practice
+Promote only the two to four identifying fields per FastTab that users must read at a glance without expanding — name, status, key amount — so the collapsed header summary line stays scannable. Leave the everyday working fields at `Standard`, and push rarely-touched fields (legacy compatibility fields, system timestamps, seldom-changed configuration) to `Additional`. Note that field-level `Importance = Promoted` is unrelated to action promotion on the page action bar; it governs FastTab field visibility only. Do not rely on initial expand or collapse state, which you cannot set programmatically and which the platform may personalize per user — design assuming any FastTab may be collapsed.
+
+## Anti Pattern
+Setting `Importance = Promoted` on most fields of a FastTab so "everything is important" defeats progressive disclosure: the collapsed summary line overflows and conveys nothing at a glance. The opposite failure is marking frequently edited fields `Additional`, forcing users to click "Show more" on every record. A detectable signal is a FastTab whose fields are nearly all `Promoted`, or a FastTab containing only `Additional` fields, which renders as an empty tab until expanded.

community/knowledge/ui/page-background-tasks.md

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+---
+bc-version: [all]
+domain: ui
+keywords: [enqueuebackgroundtask, async-calculation, child-session, factbox, cue-tile, onaftergetcurrrecord, responsive-page, read-only]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Offload Slow Read-Only Page Calculations To Background Tasks
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+Pages that compute statistics, aggregates, or external lookups inline block the page from rendering until the calculation finishes, producing a visible freeze on FactBoxes, cue tiles, and calculated fields. Business Central provides page background tasks: `CurrPage.EnqueueBackgroundTask` runs a dedicated codeunit in a read-only child session and returns values via `OnPageBackgroundTaskCompleted`, so the page opens immediately and fills in computed values as they arrive. This matters because users should never wait on a calculation they may not need. The mechanism has specific rules that are easy to get wrong, which is why it warrants an explicit pattern.
+
+## Best Practice
+Move any noticeable read-only computation off the synchronous render path into a background task. Enqueue from `OnAfterGetCurrRecord` so the task is tied to the currently focused record, and pass small payloads through the `Dictionary of [Text, Text]` input/output, converting types with `Format` and `Evaluate`. Keep each task focused on one value or a small related set rather than one large task, and show a placeholder until results land. Because tasks auto-cancel when the page closes, the record changes, or a same-ID task is re-enqueued, always supply sensible defaults and handle the timeout path in `OnPageBackgroundTaskError` — never let critical functionality depend on completion. For tests, drive the task synchronously with `RunPageBackgroundTask`.
+
+## Anti Pattern
+Enqueuing from `OnAfterGetRecord` on a list page fires the task for every row, and each cancels the instant the selection moves to the next row — pure wasted child-session churn; a reviewer spots `EnqueueBackgroundTask` called from `OnAfterGetRecord` (or from `OnOpenPage`, where the record context is not yet stable). The other tell is a task codeunit attempting a database write or `Modify`: background tasks run read-only and the write fails at runtime. Inline heavy calculation directly in `OnAfterGetCurrRecord` with no task at all is the baseline smell — it reintroduces the page freeze the feature exists to remove.

community/knowledge/ui/prefer-actionref-syntax-for-promoted-actions.md

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+---
+bc-version: [21..]
+domain: ui
+keywords: [actionref, promoted-actions, area-promoted, promotedcategory, promotedonly, action-bar, legacy-syntax]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Promote Actions With The Modern `actionref` Syntax, Never The Legacy `Promoted` Properties
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+Business Central 2022 release wave 2 (v21) introduced the `area(Promoted)` block with `actionref` as the way to promote page actions, separating an action's definition from its promotion. The older approach set `Promoted`, `PromotedCategory`, `PromotedOnly`, and `PromotedIsBig` directly on each action. The two syntaxes cannot be mixed within a single page or page extension, and choosing the legacy one entangles definition with presentation, making the action bar harder to maintain and to extend.
+
+## Best Practice
+For new pages and page extensions, define actions in their normal `area`, then promote selected ones with `actionref` inside `area(Promoted)`, grouping them under explicit categories such as `Category_Process` and entity-named groups. This keeps each action defined once and referenced where it should appear, supports split buttons via `ShowAs`, and lets an extension promote a base action without redefining it. When extending a page, you may use modern syntax even if the base page used legacy properties (and vice versa) — the no-mixing rule is per-object, not per-dependency-tree.
+
+## Anti Pattern
+Setting `Promoted = true` (with `PromotedCategory`, `PromotedOnly`, or `PromotedIsBig`) on actions in new code, or attempting to combine those properties with an `area(Promoted)` block in the same object — the latter fails to compile. The reviewer signal is any `Promoted`-prefixed property on an action in a newly authored page or page extension; flag it and convert to `actionref` (VS Code offers an automated conversion). Note separately that once an action is promoted in a published app, removing the promotion is a breaking change (AS0031/AW0013), so promote conservatively rather than walking it back later.

community/knowledge/ui/promoted-action-groups.md

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+---
+bc-version: [21..]
+domain: ui
+keywords: [action-groups, area-promoted, actionref, showas, split-button, group-caption, navigate-group, entity-group]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Use Standard Promoted Action Group Names And Placements
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+Business Central ships a fixed vocabulary of promoted action groups, and users build muscle memory around where each kind of action lives. When you define `area(Promoted)` groups, reusing the standard caption and placement for a given action class makes the page feel native; inventing your own caption or putting an action in the wrong group forces every user to relearn your page. Frontier models tend to emit plausible-but-nonstandard captions (`Go To`, `Vendor Actions`, `Related`) instead of the established BC names, which is exactly what breaks cross-page consistency.
+
+## Best Practice
+Map each action to its conventional group and use the exact standard caption: `Home`/`Process` for data-modifying and workflow actions (entity/card/document pages use `Home`, lists and worksheets use `Process`); an entity-named group (`Customer`, `Item`, `Order`) for navigation tied to the current record (statistics, ledger entries, dimensions); `Navigate` for related pages that are useful regardless of the selected record; `Report` for printing and analysis; and the workflow groups `Posting`, `Release`, `Approve`, `Request Approval`, and `Prepare` for their respective document lifecycle actions. Only `Posting` (Post / Post and Print / Preview) and `Release` (Release / Reopen) should render as split buttons via `ShowAs = SplitButton`; everything else is a normal dropdown. Within a common group keep the same action sequence you see on the matching base-app page (e.g. mirror Sales Order for a sales document) so order stays predictable.
+
+## Anti Pattern
+Custom captions for what is really a standard group (`Vendor Actions` instead of the `Vendor` entity group, `Go To` instead of `Navigate`), posting or statistics actions dropped into the wrong group, or many tiny one-action groups that fragment the ribbon. The reviewer signal is an `area(Promoted)` block whose `group` captions do not match the base-application names for the same page type, or a `ShowAs = SplitButton` on anything other than `Posting`/`Release`.

community/knowledge/ui/split-button-standard-groups.md

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+---
+bc-version: [21..]
+domain: ui
+keywords: [showas, splitbutton, promoted-actions, actionref, posting-actions, release-action, action-bar]
+technologies: [al]
+countries: [w1]
+application-area: [all]
+---
+# Reserve `ShowAs = SplitButton` For Standard Posting And Release Groups
+
+> Contributions welcome — open a PR to refine or extend this article.
+
+## Description
+Setting `ShowAs = SplitButton` on a `group` inside `area(Promoted)` renders a primary one-click button with a dropdown of related alternatives, where the FIRST `actionref` in the group becomes the primary (left) button. Business Central users have learned this pattern from the two standard groups it ships with — Posting (`Post`, `Post and Print`, `Post and Send`, `Preview Posting`) and Release (`Release`, `Reopen`). Inventing new split-button groups for unrelated actions, or ordering the dropdown so the most common action is not first, breaks that learned muscle memory and makes users guess what the left button will do.
+
+## Best Practice
+Use `ShowAs = SplitButton` only when all hold: the actions are genuinely variations of one operation, there is an obvious most-frequent primary, and the dropdown stays at roughly two to four items. Place that primary action as the first `actionref` so it occupies the left button; order the remaining refs by descending frequency. Outside the Posting and Release conventions, treat a new split-button group as something to justify, not a default — a plain promoted group or category is usually the safer choice and keeps the action bar predictable.
+
+## Anti Pattern
+Grouping unrelated actions under one split button to save toolbar space — for example pairing `Post` with `Delete`, or `Release` with `Print` — so the left button performs whatever happens to be listed first. The reviewer signal is a group with `ShowAs = SplitButton` whose member `actionref`s do not share a verb or workflow, a primary that is not the most common action, or a dropdown padded well beyond four items. Each makes the immediate left-click unpredictable and costs the user the very click the split button was meant to save.