feat: reduce three-column parity-transition churn during new-pane #111

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Closed

opened 2026-04-28 01:57:58 +00:00 by barrettruth · 0 comments

barrettruth commented

2026-04-28 01:57:58 +00:00

Problem

Even after the trivial three-column first-side-column birth is fixed, later transitions still cause nonlocal role shifts. In particular, some parity changes increase the middle-column count and force a pane to cross from the right column into the middle column.

Blocked by: #101, #102, #107

Proposed solution

Investigate and, where possible, reduce visible churn during three-column parity transitions. Scope includes:

the first time the middle column appears (s = 1)
later even-stack transitions where middle_n increases and a pane crosses columns

The goal is to reduce avoidable movement and clearly distinguish what is structurally necessary.

Context

The current matrix classifies these as local role-shift cases. Surveyed external analogs mostly rely on reprojection or explicit move-pane churn for comparable multi-column layouts.

Acceptance notes

Reduce unnecessary cross-column motion if possible.
If perfect elimination is not possible, make the residual behavior precise enough to test and later document.
Do not regress the simpler first-side-column case.

Alternatives considered

Accept full reprojection forever.
Change semantic pane-distribution rules instead of improving creation-time behavior.

## Problem Even after the trivial `three-column` first-side-column birth is fixed, later transitions still cause nonlocal role shifts. In particular, some parity changes increase the middle-column count and force a pane to cross from the right column into the middle column. Blocked by: #101, #102, #107 ## Proposed solution Investigate and, where possible, reduce visible churn during `three-column` parity transitions. Scope includes: - the first time the middle column appears (`s = 1`) - later even-stack transitions where `middle_n` increases and a pane crosses columns The goal is to reduce avoidable movement and clearly distinguish what is structurally necessary. ## Context The current matrix classifies these as local role-shift cases. Surveyed external analogs mostly rely on reprojection or explicit `move-pane` churn for comparable multi-column layouts. ## Acceptance notes - Reduce unnecessary cross-column motion if possible. - If perfect elimination is not possible, make the residual behavior precise enough to test and later document. - Do not regress the simpler first-side-column case. ## Alternatives considered - Accept full reprojection forever. - Change semantic pane-distribution rules instead of improving creation-time behavior.