merge: RawBrowseModal post-await staleness guard (deferment §0.1 race ported from the 2026-08-05 sibling fix)

src/Server/ZB.MOM.WW.OtOpcUa.AdminUI/Components/Shared/Raw/RawBrowseModal.razor

@@ -279,6 +279,15 @@
     [Parameter] public EventCallback OnSaved { get; set; }
 
     private bool _open;             // guards re-seeding on unrelated re-renders
+
+    /// <summary>
+    ///     Identifies WHICH open a post-await write belongs to. <see cref="_open"/> is a bool and cannot
+    ///     tell two opens apart, and Blazor does not serialize <c>OnParametersSetAsync</c> against its own
+    ///     outstanding task — so a close-reopen onto another device overlaps the first open's resolve, and
+    ///     last-completion-wins would point "Connect &amp; browse" at a controller nobody is looking at.
+    /// </summary>
+    private int _openGeneration;
+
     private bool _resolving;
     private bool _canBrowse;
     private string? _disabledReason;
@@ -348,6 +357,8 @@
 
     private async Task ResetAndResolveAsync()
     {
+        var generation = ++_openGeneration;
+
         _token = Guid.Empty;
         _opening = false;
         _openError = null;
@@ -374,6 +385,10 @@
             // Merged Driver+Device config — endpoint lives in DeviceConfig in v3, so the browser must dial
             // the merged blob (same merge the driver-probe/test-connect path uses).
             var merged = await Svc.LoadMergedProbeConfigAsync(DeviceId);
+            // A superseded open must never install its device under the displayed modal — see
+            // _openGeneration. Every post-await write below is behind this check.
+            if (IsStale(generation)) { return; }
+
             if (merged is { } m)
             {
                 _driverType = m.DriverType;
@@ -384,6 +399,8 @@
             if (!string.IsNullOrEmpty(TagGroupId))
             {
                 var ctx = await ExportReader.ResolveGroupContextAsync(TagGroupId!);
+                if (IsStale(generation)) { return; }   // same race, second await: this one retargets the commit
+
                 if (ctx is { } c)
                 {
                     _groupPrefix = c.GroupPath;
@@ -401,16 +418,37 @@
         }
         catch (Exception ex)
         {
-            _canBrowse = false;
-            _disabledReason = $"Could not load device config: {ex.Message}";
+            // A superseded open that FAILS is the same defect wearing the catch block: its diagnostic
+            // names a device the operator is no longer looking at, and it would disable browsing for the
+            // one they are.
+            if (!IsStale(generation))
+            {
+                _canBrowse = false;
+                _disabledReason = $"Could not load device config: {ex.Message}";
+            }
         }
         finally
         {
-            _resolving = false;
-            StateHasChanged();
+            // The tail state belongs to an open too: `return`ing out of the try above still runs this, so
+            // an unguarded finally would drop the LIVE open's spinner mid-resolve and render the
+            // half-reset panel underneath it.
+            if (!IsStale(generation))
+            {
+                _resolving = false;
+                StateHasChanged();
+            }
         }
     }
 
+    /// <summary>
+    ///     Whether the open that captured <paramref name="generation"/> has been superseded — by a later
+    ///     open, or by the modal being closed outright (a close raises no new generation, so
+    ///     <see cref="Visible"/> is the half that catches it).
+    /// </summary>
+    /// <param name="generation">The <see cref="_openGeneration"/> value captured when the open started.</param>
+    /// <returns><see langword="true"/> when no state may be written for that open.</returns>
+    private bool IsStale(int generation) => generation != _openGeneration || !Visible;
+
     private async Task OpenBrowseAsync()
     {
         _opening = true;