About

Both grids use a rowHeightProvider (every 13th row 70px, every 5th row 32px, else 25px). Grid A freezes the first two columns; Grid B freezes the first two columns and the first three rows. Row nodes are cloned per column pane, so the checks assert that left/right panes agree on every row's top and height, and that the frozen row pane is exactly as tall as the rows it holds.

Controls

Run frozen geometry self-checks A: grow row 2 by 10px (invalidateRowHeights) B: grow frozen row 0 by 10px (invalidateRowHeights) Scroll both to row 300 (top)