diff --git a/packages/csr/src/reactive-runtime.ts b/packages/csr/src/reactive-runtime.ts
index 0dcdd0e6..ebb99d25 100644
--- a/packages/csr/src/reactive-runtime.ts
+++ b/packages/csr/src/reactive-runtime.ts
@@ -2886,6 +2886,32 @@ export const REACTIVE_RUNTIME = String.raw`
     });
   }
 
+  /*
+   * One document observer, several subscribers. The filter stays explicit:
+   * observing every attribute would see the tabindex the roving code writes
+   * and loop on its own output.
+   */
+  var documentWatchers = [];
+
+  function watchDocument(handler) {
+    documentWatchers.push(handler);
+  }
+
+  function startDocumentWatch() {
+    if (window.__wrnexusDocWatchBound || typeof MutationObserver !== "function") return;
+    window.__wrnexusDocWatchBound = true;
+    new MutationObserver(function () {
+      for (var index = 0; index < documentWatchers.length; index += 1) documentWatchers[index]();
+    }).observe(document.documentElement, {
+      subtree: true,
+      childList: true,
+      attributes: true,
+      // prettier-ignore
+      attributeFilter: ["data-open","data-show","class","style","hidden",
+        "data-placement","aria-selected","aria-current","disabled","aria-disabled"],
+    });
+  }
+
   function setupAnchoredOverlays() {
     if (window.__wrnexusAnchoredBound) return;
     window.__wrnexusAnchoredBound = true;
@@ -2894,14 +2920,7 @@ export const REACTIVE_RUNTIME = String.raw`
     // root, data-show on the panel, a class), so watch for any attribute or
     // structural change and re-measure on the next frame instead of trying to
     // enumerate every signal.
-    if (typeof MutationObserver === "function") {
-      new MutationObserver(scheduleAnchoredReposition).observe(document.documentElement, {
-        subtree: true,
-        childList: true,
-        attributes: true,
-        attributeFilter: ["data-open", "data-show", "class", "data-placement"],
-      });
-    }
+    watchDocument(scheduleAnchoredReposition);
 
     window.addEventListener("resize", scheduleAnchoredReposition);
     window.addEventListener("scroll", scheduleAnchoredReposition, true);
@@ -3027,19 +3046,11 @@ export const REACTIVE_RUNTIME = String.raw`
     if (window.__wrnexusDialogsBound) return;
     window.__wrnexusDialogsBound = true;
 
-    if (typeof MutationObserver === "function") {
-      new MutationObserver(function () {
-        // Same deferral as the anchored clamp: the mutation that opens a
-        // dialog is the one that makes it visible, so it still measures as
-        // hidden until the panel has been laid out.
-        window.setTimeout(syncDialogs, 0);
-      }).observe(document.documentElement, {
-        subtree: true,
-        childList: true,
-        attributes: true,
-        attributeFilter: ["data-open", "data-show", "class", "style", "hidden"],
-      });
-    }
+    // Deferred: the mutation that opens a dialog is the one that makes it
+    // visible, so it is not laid out yet when the record arrives.
+    watchDocument(function () {
+      window.setTimeout(syncDialogs, 0);
+    });
 
     document.addEventListener("keydown", trapDialogTab, true);
     syncDialogs();
@@ -3157,16 +3168,9 @@ export const REACTIVE_RUNTIME = String.raw`
 
     document.addEventListener("keydown", handleRovingKeydown, true);
 
-    if (typeof MutationObserver === "function") {
-      new MutationObserver(function () {
-        window.setTimeout(syncRovingGroups, 0);
-      }).observe(document.documentElement, {
-        subtree: true,
-        childList: true,
-        attributes: true,
-        attributeFilter: ["aria-selected", "aria-current", "disabled", "aria-disabled", "hidden"],
-      });
-    }
+    watchDocument(function () {
+      window.setTimeout(syncRovingGroups, 0);
+    });
 
     syncRovingGroups();
   }
@@ -3240,11 +3244,9 @@ export const REACTIVE_RUNTIME = String.raw`
       for (var index = 0; index < navs.length; index += 1) wireScrollspy(navs[index]);
     };
     wireAll();
-    if (typeof MutationObserver === "function") {
-      new MutationObserver(function () {
-        window.setTimeout(wireAll, 0);
-      }).observe(document.documentElement, { subtree: true, childList: true });
-    }
+    watchDocument(function () {
+      window.setTimeout(wireAll, 0);
+    });
   }
 
   function hydrateScopes(root) {
@@ -5466,6 +5468,7 @@ export const REACTIVE_RUNTIME = String.raw`
   setupModalDialogs();
   setupRovingFocus();
   setupScrollspy();
+  startDocumentWatch();
   window.__wrnexusRepositionAnchored = repositionAnchored;
   window.__wrnexusHydrateScopes = hydrateScopes;
   window.__wrnexusInvalidateClientModule = function (url) { clientModuleCache.delete(url); };