[masarray]

Exact stack and hard boundaries

• Base is ARSAS draft P0 IEC 61850 parity: verified ST/SE DO reads + final nonqueued control admission #668 exact 677323d; not main and not blocked BLOCKED P0 SBO timing FAT trial: exact engine #187 pin requires provenance-guard qualification #666.
• Keep engine lock at qualified fix: bind Signal Selection one-to-one to static DataSet members #184 9c7cb40364023a7b217e5ec31ab3105ba90142eb; engine fix: stop UI policy deleting static DataSet inventory #187 remains separate/unpromoted.
• No MMS write, new automatic whole-IED RCB polling, fake occupancy indicator, SCL-as-live-value, control change, GOOSE/SMV overlap.

Root cause and implementation

• MainWindow.IedBrowser.cs previously explicitly auto-expanded Reports->first LD->first LN for each fresh selected IED. Remove auto-expansion, preserve same-model/current-association user-expanded keys, reset on model or association epoch change. Reports selection continues to show right-hand list without left subtree expansion.
• RCB ?/●/◆ glyph came from operational occupancy, not the actual Boolean RptEna. Introduce one read-only index of uniquely model-matched BR/RP RptEna targets for coalesced visible UI projection; only current association's explicit MMS Read result with strict Boolean true can light the operator's exact circular open-padlock vector. The user-supplied Geometry remains a WPF resource SSOT. False/unknown/disconnect/other association/traffic-only/owned-only -> blank.
• Dedicated BrowserRcbObjectRow uses fixed ~200px name and adjacent 24px icon slot. Non-RCB objects retain their previous content template and full-width labels. Existing virtualized tree/detail rows are updated in place; no navigation reset for ordinary live changes.

Regression tests

• New P0BrowserRcbEnabledTruthTests: true/false, noncanonical/untyped text, report-only, wrong FC, other RCB, duplicate declaration, offline/reconnect/old association, six collapsed categories/explicit restored paths, original SVG and compact inline cell.
• Update preexisting ownership regression, correctly preventing RptEna TRUE assertions from caller-owned runtime activation alone.

Validation pending

This is a DRAFT, not field/production acceptance. Require exact-head Windows CI, app+engine+package test counts, native bridge + portable PE smoke and screenshot at 1666x900 and 1280px; verify one RptEna true after exact read, no icon without read or on association epoch change. No main merge/release without existing R7/R10 qualification and FAT evidence.

[masarray]

Housekeeping 2026-10-23: this exact PR HEAD c5b3003773e7e38ae6b464007e79e325c229056f is an ancestor of staging/global-mms-write-browser-control-20261023 (GitHub compare: ahead=128, behind=0). Scoped changes already exist in staging. Closing superseded/integrated into staging, NOT merged to main and NOT approved physical FAT. No engine lock/production promotion; further Write/Control work is tracked in staged PR #690.