The grid background a cell renders with, cascading cell fill → the sheet's normal-style fill →
the grid body fill. This is the grid's rendering rule (not a cell property), so the grid editor box
uses it to cover the cell while editing. The cell-aware input itself paints only the cell's own
fill; this fallback is the container's job.
The grid background a cell renders with, cascading cell fill → the sheet's normal-style fill → the grid body fill. This is the grid's rendering rule (not a cell property), so the grid editor box uses it to cover the cell while editing. The cell-aware input itself paints only the cell's own fill; this fallback is the container's job.