history

Default LabKit close protection

id: LK-20260709-default-labkit-close-protection
date: 2026-07-09
sequence: 43
type: fix
compatibility: compatible
component: `labkit.ui` | `5.0.2 -> 5.0.3`
component: `labkit_FocusStack_app` | `1.4.6 -> 1.4.7`
component: `labkit_ImageEnhance_app` | `1.5.5 -> 1.5.6`
component: `labkit_ImageMatch_app` | `1.5.5 -> 1.5.6`
scope: Default LabKit close protection

Context

Only apps that installed a dirty-state guard warned before closing. A newly created public or private app could therefore discard work silently until its author implemented and tested a separate guard. Repeated close shortcuts could also race with a modal confirmation.

Decision and rationale

Make close confirmation a default property of every framework-owned app window and remove the optional app-facing guard API. Keep one in-window prompt active at a time; a repeated close shortcut confirms that prompt instead of opening another one.

Changes

• labkit.ui 5.0.2 -> 5.0.3
• labkit_FocusStack_app 1.4.6 -> 1.4.7
• labkit_ImageEnhance_app 1.5.5 -> 1.5.6
• labkit_ImageMatch_app 1.5.5 -> 1.5.6

• LabKit runtime figures now show an in-window confirmation prompt before any framework-owned app window closes, even when the app has not marked itself dirty.
• Removed the app-facing labkit.ui.runtime.setCloseGuard API and migrated existing app close-guard dirty checks to the framework default behavior.
• Repeating or holding the app close shortcut while the in-window prompt is active confirms the close.

User and data impact

Every public or private LabKit app asked before its window closed, even if the app had no custom dirty-state logic. Users gained a consistent protection against accidental closure at the cost of one confirmation step.

Compatibility and migration

• Closing LabKit apps now requires one confirmation step by default. App code that calls labkit.ui.runtime.setCloseGuard must remove that call; close confirmation is framework-owned.

Validation

Commit 0c9f472b expanded the UI busy-state GUI suite for initial close, cancel, confirmation, and repeated-shortcut behavior, then updated public- surface and app-compatibility checks.

Evidence

• Mainline commit 0c9f472b.

Known limitations and follow-up

This policy protected the window, not the semantic completeness of each saved project. Runtime V2 later combined default close handling with app-owned dirty state and lifecycle services.