Panel Contributions

Panel Contributions let any panel publish toolbar items and sidebar sections that are shown only while that panel is the active one (state.activePanelId). Two instances of the same panel type — two maps, two documents — stay fully independent: nothing here is shared or keyed globally, so switching between them always reflects each instance's own state.

Distinct from Panel Overlay

Panel Overlay → renders toolbars and floating windows inside a single panel's own DOM boundary — invisible to the rest of the app. Panel Contributions is the opposite direction: a panel reaches outward, publishing content that the workspace-level <RddToolbar>/<RddSidebar> renders on its behalf, only while it's active.

When to use it

• A map panel that shows different tool buttons (Pan / Draw / Measure) depending on which controller is currently installed — with two open maps keeping independent selections.
• A document/editor panel contributing a live "Table of Contents" sidebar section, extracted from its own content.
• Any panel-specific action (formatting buttons, view toggles, search) that belongs in the app's shared chrome only while that panel has focus, instead of cluttering it permanently.

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usePanelContribution(contribution)

Call inside a panel component, on every render, to publish what it wants shown. Republishes automatically when contribution changes; cleared automatically on unmount. Throws if used outside a DockableDesktopProvider tree.

import { usePanelContribution } from 'react-dockable-desktop';

function MapPanel() {
  const [controller, setController] = useState<'pan' | 'draw' | 'measure'>('pan');

  usePanelContribution({
    toolbarItems: (['pan', 'draw', 'measure'] as const).map(id => ({
      type: 'toggle',
      id,
      label: id,
      icon: icons[id],
      active: controller === id,          // self-reported — not ToolbarContext's shared state
      onToggle: () => setController(id),
    })),
    sidebarSections: [
      { id: 'layers', label: 'Layers', content: <LayerList /> },
    ],
  });

  // ...
}

Why active is on the item, not in ToolbarContext: ToolbarToggleItem/ToolbarRadioItem's uncontrolled state lives in the shared ToolbarContext, keyed by a plain string id — two panel instances contributing the same id would collide. Passing active explicitly (a controlled toggle, see Toolbar →) makes each instance's selection its own.

Memoize the object you pass (useMemo/useCallback for its arrays and callbacks) to avoid republishing on every unrelated re-render.

PanelContribution

Field	Type	Description
toolbarItems?	ToolbarItem[]	Same type <RddToolbar items={...}> already accepts — no adapter needed.
sidebarSections?	PanelSidebarSection[]	{ id, label, icon?, content } — see useMergedSidebarTabs below for how these become SidebarTabs.

Both fields are independent — contribute only toolbar items, only sidebar sections, both, or neither.

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useActiveContribution()

Reads state.activePanelId and returns whatever that panel last published via usePanelContribution(), or null if no panel is active or it contributed nothing. This is the raw, manual-control primitive — for the common case, prefer the two hooks below.

const active = useActiveContribution();
// active?.toolbarItems, active?.sidebarSections

---

useMergedToolbarItems(staticItems) / useMergedSidebarTabs(staticTabs)

Convenience wrappers around useActiveContribution() for the app shell — call once, get back a ready-to-render array, no manual splicing:

import { useMergedToolbarItems, useMergedSidebarTabs, RddToolbar, RddSidebar } from 'react-dockable-desktop';

function AppShell() {
  const toolbarItems = useMergedToolbarItems(myStaticToolbarItems);
  const sidebarTabs = useMergedSidebarTabs(myStaticSidebarTabs);

  return (
    <>
      <RddToolbar items={toolbarItems} />
      <RddSidebar tabs={sidebarTabs}>{/* ... */}</RddSidebar>
    </>
  );
}

useMergedToolbarItems appends the active panel's contributed items behind a separator; returns staticItems unchanged when there's nothing to add. useMergedSidebarTabs appends contributed sections as dynamic tabs — present only while their panel is active, never stealing focus from whichever tab the user already has open — converting each section via sectionToTab under the hood. SidebarTab.icon is optional but recommended unless the tab is hidden, so pass a second fallbackIcon argument if your sections may omit one.

Both are optional — useActiveContribution() stays fully usable for manual control (a different merge position, no separator, etc.).

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sectionToTab(section, fallbackIcon?)

The pure converter useMergedSidebarTabs uses internally, exported for manual use:

function sectionToTab(section: PanelSidebarSection, fallbackIcon?: React.ReactNode): SidebarTab

PanelSidebarSection.content is already a rendered ReactNode (not a callback), so the conversion is a straightforward renderContent: () => section.content plus an icon fallback. SidebarTab's eagerMount/preserveState have no contribution-side equivalent and are left unset — a contribution only exists while its owning panel is mounted and active.

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Worked example: two independent maps

function MapPanel({ panelId }: { panelId: string }) {
  const [controller, setController] = useState<'pan' | 'draw' | 'measure'>('pan');

  usePanelContribution({
    toolbarItems: (['pan', 'draw', 'measure'] as const).map(id => ({
      type: 'toggle', id, label: id, icon: icons[id],
      active: controller === id, onToggle: () => setController(id),
    })),
  });

  return <MapView onControllerChange={setController} />;
}

Open two MapPanel instances. Select "Draw" on the first, switch to the second (still "Pan" by default), select "Measure" there, then switch back to the first — it's still on "Draw," exactly as left. Nothing extra was needed for this: docked/floating panels stay mounted while inactive, so each instance's own controller state was never at risk — the contribution mechanism just reflects whichever instance is currently active.

Panels must be focused, not just opened

openPanel() sets state.activePanelId by default, so a freshly-opened panel's contributions show up immediately. If you ever open with { focus: false } (to preload something in the background), call focusPanel(id) when you actually want its contributions to appear.

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TypeScript exports

All exported from 'react-dockable-desktop':

Export	Kind	Description
usePanelContribution	Hook	Publish this panel's toolbar items/sidebar sections while active
useActiveContribution	Hook	Read the active panel's published contribution manually
useMergedToolbarItems	Hook	staticItems + active contribution's toolbar items, ready for <RddToolbar items={...}>
useMergedSidebarTabs	Hook	staticTabs + active contribution's sections as dynamic tabs, ready for <RddSidebar tabs={...}>
sectionToTab	Function	Pure PanelSidebarSection → SidebarTab converter
PanelContribution	Interface	{ toolbarItems?, sidebarSections? }
PanelSidebarSection	Interface	{ id, label, icon?, content }

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See also

• Toolbar → — workspace-level tool strip; ToolbarToggleItem's controlled active field
• Panel Overlay → — panel-scoped toolbars and floating windows (the other direction)
• Panel Lifecycle & Forms → — usePanel() and the panel lifecycle hooks