The model (the workbook, for the built-in panes).
The activation argument, if the pane accepts one — see args.
OptionalargsWhat the activating call asked this pane to show — ActivateFrameOptions.args, delivered
verbatim.
The pane defines the shape; the area only carries it. It is scoped to one activation rather than to the pane's lifetime: activating again without it clears it, and re-delivering the same payload means passing it again. So a pane treats an arriving value as an EVENT — react to it changing, not to its presence, or a re-render replays it.
undefined is the ordinary case: opened from the ribbon, a pane is asked for nothing in
particular.
The key used to register the taskPane.
OptionalframeOptionalmodelOptionalrefRef to the task pane's root element (React 19 ref-as-prop).
Props passed to a registered task pane component.
Remarks
Task panes are real React components (rendered as
<Component {...props}/>), so they may use hooks freely. The host'srefarrives as a regular prop (React 19 style); forward it to the pane's root element. Extends HTML attributes because hosts may inject presentation props (propsPane) that the pane is expected to spread onto its root.