[masarray]

M2.14 Browser field UX: whole-row navigation and explicit selected DO reads

Direct base: Draft #583 756de98a2bb0 (retains #582 GOOSE and TapChg repair, live title, icons, prior A/B safety and 2,002 regression baseline). PR remains Draft and all ancestors are untouched.

Root causes fixed

• Operator can currently only expand the Objects tree by clicking a tiny chevron; details rely on chevron or double-click. Add single-click on the row in the existing virtualized DataGrid/ListView, including safe chevron Button suppression so no double toggle. Double-click retains page-navigation semantics only. No new grid, UI tree, or item materialization.
• A model LN is the deepest selectable left-navigation node. The Read handler previously read the entire LN, ignoring which Data Object the operator is working on in the detail pane. After the operator clicks a top-level DO row, explicit Read now scopes to all verified safe FC attributes in exactly that DO (ST q/t/stVal, CF ctlModel, DC d, MX etc.), not just a convenient stVal leaf. Uses the existing IedBrowserReadPlan and read service, no second client, no cyclic poll. If no DO focused, existing LN-wide Read remains. Read All remains global and unchanged.
• DO Read focus is a separate exact ReadObjectReference, never a preferred process leaf or inferred name. Model identity is constrained to the active selected LN. Focus is cleared on page navigation.
• Three focused regression tests: all safe FC attributes present, wrong LN and CO forbidden, global Read All unaffected, primary scalar preference cannot hijack DO identity.

Safety / acceptance

No automatic read on navigation, control/GI/GOOSE activation, write, MMS runtime changes, RCB, engine pin or stable/main modifications. Windows exact-SHA CI + device acceptance required. If IED rejects individual reads, unavailable stays truthful: a click or model declaration never fabricates remote values.