Panel spawn actions

Start with the layout, then name the action. This draft maps the basic ways to open a view before deciding artifact-preview reuse or a new API shape.

These are schematic illustrations, not product screenshots. They show relative placement, not exact widths. A and B are existing views; X is the view to open. A white tab is active. Amber marks an active X.

Three starting layouts

S1 — One view: a single region containing A.
S2 — Two regions: a list on the left and A on the right. A is the source.
S3 — Tab group: A and B share one region. B is active and is the source.

Three starting layouts: one view A, list beside A, and a tab group containing A and B.

A tab is one view instance. A panel region contains one or more tabs. A split arranges regions side by side or vertically. Spawning beside a tab means splitting its containing region; it does not extract that tab from its group.

The basic actions

For the first three actions below, assume X is not already open.

Action	Starting layout needed	Result	Current PageViews operation
Open as tab	An existing destination region	Add X to that region and activate it	`open` with its `panelId`
Spawn right	A source tab or region	Split its region horizontally; put X on the right	`split(id, 'right')`, then `open`
Spawn below	A source tab or region	Split its region vertically; put X below	`split(id, 'below')`, then `open`
Activate existing	X already exists somewhere in this layout	Select X in its current region; no new split or tab	`activate(tabId)` or `open` with `reuse: 'existing'`

“Spawn” here means create a view instance and place it. Moving an existing tab, docking, resizing, and closing are separate actions. Activating a tab and assigning keyboard focus are also separate concerns in the current API.

S1 — One view

Starting from A, the three spawn actions produce three different layouts. Opening a tab retains A as an inactive tab; splitting keeps A visible beside X.

From A: open X as a tab with A, split X to the right, or split X below.

S2 — Two regions

Target A’s region, not the page root. The list remains on the left. Right and below splits divide only the space currently occupied by A.

From a list beside A: add X to A's tab group, split A to the right, or split A below; the list stays in place.

S3 — A tab group

A and B already share a region. Opening X as a tab adds it to that group. Spawning right or below splits beside the whole group; A and B stay together.

From tabs A and B: add X as a third tab, spawn X right of the group, or spawn X below the group.

When X is already open

This is an independent choice from placement:

Reuse: activate the existing X wherever it is. Do not move it back beside the source.
New instance: create another X at the requested destination, leaving the original intact.

With inactive X already open beside A: activate X in place, or create another X in A's region.

In the activation illustration, tab order is simplified to mark the active view; actual activation does not reorder tabs.

The current reuse: 'existing' searches the entire layout. Resource identity excludes artifact fragments, so another slide of the same artifact reuses its tab. reuse: 'new-instance' creates a distinct instance of the same resource. The destination must still exist, even when a matching resource is already open.

Map the artifact click onto these primitives

For a first artifact-tag click from a note: spawn right of the source. For another reference to the same artifact: activate existing and navigate. These are the current openArtifactBeside behaviors.

For a different artifact, the current helper spawns another right-hand region. Once these basic actions are agreed, the next question is whether that click should instead open a tab in an existing preview region or replace a replaceable preview. Those policies are deliberately not decided here.

An ordinary web link retains browser navigation. Opening a generic web iframe is an explicit action and can use the same spawn-right primitive.

Implementation reference and scope

Source inspected in the note-artifact-panels worktree:

components/layout/views/pageViews.ts: open, activate, split, resource identity, and openArtifactBeside.
components/layout/views/PageViewLayout.tsx: native content rendering and shared tab chrome.
components/notes/NoteDetailView.tsx: finds the source tab from the clicked reference.
UIKit PanelLayout: split tree, tab groups, drag, dock, resize, and persistent content surfaces.

Current operations are described, not changed. Right/below opening currently requires two API calls; an atomic spawn request is a possible later design step. No application code or release is included.

No public skill impact: this is an internal layout-design draft, not a change to Notes content operations, CLI/SDK procedures, or distributed skill instructions.