Copilot's seventh pass. One applied, one applied by *withdrawing* the
previous fix rather than patching it again.
**`RenderColGroup::label` is an `Option<String>`.** `""` was the
ungrouped-run sentinel, but an empty string is a legal group *name* —
`Category::add_item_in_group` accepts one and the TUI draws its indicator
like any other — so a real group serialized identically to no group at all
and the page dropped its indicator on a truthiness test. `None` is now the
run in no group, and `app.js` checks for null.
**Inline group rows are no longer reserved in the viewport, and the reason
is written down.** Copilot was right twice in a row here, about two
opposite mistakes. Counting the current group rows is a feedback loop (a
smaller window crosses fewer groups and asks for a larger one). Keeping the
maximum is a ratchet: one group header per data row stores an oversized cost
on the first oversized projection and clamps the grid to a single row
*permanently*. Both were on this branch.
The third option — invent a density heuristic — is the one this repo warns
against, in a file no test here can execute. So the reservation keeps only
what depends on the axes and not on the window: the header lines, the group
line, the row-header width. The residue is an over-request bounded by the
groups in view, and the off-screen-selection gap it leaves is neither new
nor specific to groups — nothing in this page calls `scrollIntoView` at all.
Filed rather than guessed at.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Edward Langley
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