Values fitted and row labels did not. The measurement pairs each column's
header with its body cell, and for the row-header columns the header is a
blank corner cell — so the column was being sized from an empty string,
never from the labels beneath it.
Measured with a canvas instead of the DOM, for the same reason the headers
cannot size themselves: the cell is clipped, so reading its box back returns
the width it was allotted rather than the width of its text. Tree
indentation is added, since it occupies real width. The result is pinned as
a column_size_override on __ROW_PATH__ — the key
restore_column_size_overrides special-cases for this column, and an override
is what survives subsequent draws, which is precisely why overrides were
defeating resetAutoSize earlier.
Group headers are deliberately left alone. pro.css is explicit:
/* Header groups should overflow and not contribute to auto-sizing. */
thead tr:not(.rt-autosize) th { overflow: hidden; max-width: 0px; }
Only the leaf header row participates, because a group label spans many
columns and letting it set width would widen all of them. With the ordinal
prefix in front, "01 - Prior…" still reads when truncated. Fixing it
properly means distributing a group's label width across its span, which is
a different job.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Paul Trowbridge
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