Fix stale panel height when content shrinks

[fredrivett]

Problem

The reeve panel sometimes kept its old, too-tall height after its content got smaller — collapsing an environment, clearing the filter, hitting "Collapse all", or processes vanishing on a refresh would leave the list vertically centred inside an oversized window.

Root cause

The panel's height is driven by scrollContentHeight, measured by a GeometryReader in the scroll content's .background. Per the documented macOS 26 MenuBarExtra quirk, that GeometryReader only re-measures when its .id() changes. The id was tied only to inactiveExpanded, so height re-measured on the Inactive toggle but not for any other change that shrinks the content. Combined with the if h > 0 guard, scrollContentHeight stayed stuck at its old large value and never came back down.

Fix

Replace .id(inactiveExpanded) with .id(contentHeightSignature) — a composite hash of every piece of state that affects content height:

• filterText, inactiveExpanded, showInactive
• collapsedEnvironments and expandedInactiveEnvironments
• per-environment path, active state, process count, and error presence

Any change that grows or shrinks the list now recreates the GeometryReader and forces a fresh measurement, so the window resizes to fit.

Also added a Fragility note to the quirk section in AGENTS.md (which CLAUDE.md symlinks to) so future state dimensions get folded into the signature.

Testing

• swift build passes.
• Manual: expand to a tall panel, then collapse an env / clear the filter — window now snaps down to the new content height instead of leaving centred content in an oversized window.

🤖 Generated with Claude Code

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Summary by cubic

Fixes the panel keeping a too-tall height after content shrinks in the macOS 26 MenuBarExtra. The window now snaps to the correct size immediately, even when filters or refreshes change which rows are visible.

• Bug Fixes
  • Replaced the GeometryReader .id(inactiveExpanded) with .id(contentHeightSignature) to force re-measure on any height change.
  • contentHeightSignature mirrors render logic: hashes filter text, inactive toggle/visibility, collapse/expand state, per-env path/active/error presence, filter match, and the visible process count.
  • Added a fragility note in AGENTS.md to keep the signature updated when new height-affecting state is introduced.

^{Written for commit 6247d4e. Summary will update on new commits.}

[cubic-dev-ai]

All reported issues were addressed across 2 files

<sub>Reply with feedback, questions, or to request a fix.

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[fredrivett]

Good catch — valid. The signature hashed the raw per-env process count, but under an active filter the rendered rows come from filteredProcesses(for:) and envNameMatches(_:), so a refresh could change which rows match without changing the total count and leave the height stale.

Fixed in 6247d4e by mirroring the render logic: the signature now hashes matchesName plus the actual visible process count (which together also capture whether the env is shown at all), rather than the raw count.