# Retail shared main-panel placement — pseudocode

**Date:** 2026-07-17
**Symptom:** moving Inventory and then opening Character/Skills or Magic opens
the new panel at its own stale saved position instead of the position just used.

## Retail oracle

Named Sept-2013 retail symbols:

- `gmPanelUI::SetupChildren @ 0x004BC9E0`
- `gmPanelUI::RecvNotice_SetPanelVisibility @ 0x004BC6F0`
- `gmPanelUI::PostInit @ 0x004BD010`
- `gmPanelUI::ResizeTo @ 0x004BC6E0`

Verbatim `acclient.h` ownership:

```text
gmPanelUI : UIElement_Field
    SmartArray<PanelChildInfo> m_childrenInfoArray
    UIElement* m_currentlyShownPanel
    UIElement* m_previouslyShownPanel
    UIElement* m_pPanelPagesFrame
    bool m_bStretchMode

PanelChildInfo
    UIElement* child
    uint panelID
```

`SetupChildren` resolves each known panel element recursively, stores the
child pointer together with its property-`0x10000029` panel ID, and initially
hides every child. It does not create independent top-level windows.

## Retail behavior

```text
SetPanelVisibility(panelId, show):
    requested = find m_childrenInfoArray entry by panelId
    if requested is missing:
        return

    if show:
        if requested.child == m_currentlyShownPanel:
            requested.child.SetVisible(true)
            parent.SetVisible(true)
            return

        previous = m_currentlyShownPanel
        m_currentlyShownPanel = requested.child

        if previous is visible:
            if requested restores previous and previous does not:
                m_previouslyShownPanel = previous
            else:
                m_previouslyShownPanel = null
            send SetPanelVisibility(previous.panelID, false)

        requested.child.SetVisible(true)
        parent.SetVisible(true)
        return

    if requested.child == m_currentlyShownPanel:
        requested.child.SetVisible(false)
        if m_previouslyShownPanel exists:
            send SetPanelVisibility(previous.panelID, true)
            m_previouslyShownPanel = null
        else:
            m_currentlyShownPanel = null
            parent.SetVisible(false)
        return

    requested.child.SetVisible(false)
```

The decisive placement fact is structural: Inventory, Character/Skills, and
Magic are children of one `gmPanelUI`. The switch changes child visibility;
there is no child move and no per-panel top-level position. Dragging the parent
therefore moves the one position subsequently used by every child.

## acdream port shape

acdream imports these child LayoutDesc roots independently, so each currently
has its own retained wrapper. `RetailPanelUiController` already ports retail's
one-active-child and restore-previous lifecycle. Complete that logical-parent
ownership by adding one canonical placement for the primary toolbar children
(Inventory `7`, Character `11`, Magic `13`):

```text
on primary child frame moved:
    canonicalPosition = moved frame position
    move every other primary child frame to canonicalPosition

before showing a primary child:
    if canonicalPosition exists:
        move requested child frame to canonicalPosition
    else:
        canonicalPosition = requested child frame position

before hiding the active primary child:
    capture its current position as canonicalPosition
```

The controller owns this synchronization and subscribes to typed
`RetailWindowHandle.Moved` events. Toolbar commands, keyboard commands,
restore-previous effects, persistence restore, and direct window dragging all
therefore pass through the same owner. Panel-authored size/resize policy stays
with the active child; only the retail parent placement is shared.

ACE contains no client UI implementation, and the in-tree WorldBuilder
reference contains no `gmPanelUI` port, so neither supplies a competing
behavioral interpretation. The named retail client and verbatim header are the
oracle for this UI ownership rule.