ConstModeled on Excel Online's format pane, with two deliberate departures.
The preview is shared. Excel Online gives each of its panels its own sample, which means the font sample cannot show you the number format and the number sample cannot show you the fill. One preview of the actual anchor cell answers every tab at once — and since the pane applies live, it is not a mock of the result, it IS the result.
There is a Fill tab, which Excel Online has no equivalent for: the model carries pattern and gradient fills, and burying them the way desktop Excel does (a "Fill Effects" sub-dialog) is not worth copying. See FillPanel.
The Format Cells task pane: one preview over five tabs, applying live to the selection.