diff --git a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Shared/TreeView.razor b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Shared/TreeView.razor
index f5df349b..b46c3655 100644
--- a/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Shared/TreeView.razor
+++ b/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Shared/TreeView.razor
@@ -51,6 +51,12 @@ else
                 @oncontextmenu="(e) => OnContextMenu(e, item)" @oncontextmenu:preventDefault="@(ContextMenu != null)" @oncontextmenu:stopPropagation="@(ContextMenu != null)">
                 @if (isBranch)
                 {
+                    @* preventDefault on the toggle's keydown suppresses Space-bar page scroll on activation
+                       (intended for a role=button). It also suppresses Arrow-key default scroll while the toggle
+                       itself has focus — acceptable, as the chevron is Tab-navigated and Blazor offers no per-key
+                       conditional preventDefault. This comment MUST stay OUTSIDE the start tag: a Razor comment
+                       placed between attributes is emitted as an invalid attribute name and crashes the render
+                       (InvalidCharacterError → circuit teardown on any tree with branch nodes). *@
                     <span class="tv-toggle"
                           role="button"
                           tabindex="0"
@@ -59,9 +65,6 @@ else
                           @onclick="() => ToggleExpand(key)"
                           @onclick:stopPropagation
                           @onkeydown="(e) => OnToggleKey(e, key)"
-                          @* preventDefault suppresses Space-bar page scroll on activation (intended for a role=button).
-                             It also suppresses Arrow-key default scroll while the toggle itself has focus — acceptable,
-                             as the chevron is Tab-navigated and Blazor offers no per-key conditional preventDefault. *@
                           @onkeydown:preventDefault><i class="bi bi-chevron-right"></i></span>
                 }
                 else