ADR 0224: Right Panel Tab Strip and Data-Driven Add Menu

• Status: Accepted
• Date: 2026-09-11
• Related issue: #229

Context

The right work panel used one header menu for both tool launchers and conversation-opened resources. That made open resources harder to scan, put close actions far from their tabs, and allowed the menu to become a second scrolling surface. The issue's HTML demo establishes the intended structure and interaction shape, but its simulated content is not an application data source.

Decision

The work-panel header is a horizontally scrollable tab strip followed by a fixed, tight + trigger. The strip is the only horizontally scrolling region; the + remains visible. Every open Review, file, or plugin view is represented by one ARIA tab. Tabs activate on click, close on their hover/focus close button or middle-click, and support ArrowLeft/ArrowRight/Home/End plus Delete/Backspace. Closing the final tab keeps the panel open and shows a New launcher in the body.

The + menu has one Tools & panels group. Review is the only host-owned entry; all other entries come from the current plugin-view metadata returned by contributes.views. The renderer must not hardcode bundled Files or Browser entries, and must not show shortcut labels unless the corresponding binding is actually registered. Open plugin views remain singleton tabs and reopening one activates its existing tab.

The viewport-fixed panel toggle remains the sole collapse control. It uses the two-state panel icon, aria-pressed, and a localized tooltip/accessibility name that includes the user's resolved Mod+J binding when one exists. The binding remains customizable through the existing keyboard-shortcut machinery.

The new-profile default panel width is 360px within the existing 244–720px range. A saved width is not rewritten by this change. No protocol, persisted tab schema, plugin manifest, or native-window reservation is introduced.

Consequences

• The tab strip makes the active resource and its close affordance visible while preserving panel width and the existing native-surface occlusion boundary.
• The New launcher gives an intentional next action after the last tab closes without changing the panel's session-scoped state model.
• Plugin authors automatically receive a panel launcher whenever their scoped view contribution is available; the host's built-in list does not drift from plugin metadata.
• The larger default gives the header enough room for the 166px Windows/Linux titlebar reservation while preserving existing user-selected widths.