diff --git a/static/cmap/controller/cmap-interaction-controller.js b/static/cmap/controller/cmap-interaction-controller.js
index 43e5edc..6759a51 100644
--- a/static/cmap/controller/cmap-interaction-controller.js
+++ b/static/cmap/controller/cmap-interaction-controller.js
@@ -9,6 +9,7 @@ export class CmapInteractionController {
     this.activeMarqueeCleanup = null;
     this.canvasPanPointerDownHandler = null;
     this.activeCanvasPanCleanup = null;
+    this.boundaryRefreshScheduled = false;
   }
 
   get items() { return this.editor.items; }
@@ -24,9 +25,19 @@ export class CmapInteractionController {
       this.moveSubmapGroup(record, x, y, moveMembership);
       queueMicrotask(() => this.redrawAllConnectors());
     }
+    this.scheduleBoundaryRefresh();
     return { x, y };
   }
 
+  scheduleBoundaryRefresh() {
+    if (this.boundaryRefreshScheduled) return;
+    this.boundaryRefreshScheduled = true;
+    window.requestAnimationFrame(() => {
+      this.boundaryRefreshScheduled = false;
+      if (!this.editor.destroyed) this.editor.refreshBoundaryReferences();
+    });
+  }
+
   beginItemMove(record, includeDescendants = false) {
     if (record.moveMembership) return record.moveMembership;
     let groupItems = [record];
diff --git a/static/cmap/view/cmap-item-decorator.js b/static/cmap/view/cmap-item-decorator.js
index dba59e1..040434a 100644
--- a/static/cmap/view/cmap-item-decorator.js
+++ b/static/cmap/view/cmap-item-decorator.js
@@ -2,6 +2,8 @@
 
 import { debug, elementDescription, selectionStyle, escapeHtml } from "../cmap-utils.js";
 
+const BOUNDARY_LINE_COLOR = "#77838e";
+
 export class CmapItemDecorator {
   constructor(editor) {
     this.editor = editor;
@@ -457,7 +459,7 @@ export class CmapItemDecorator {
     marker.setAttribute("orient", "auto-start-reverse");
     const arrow = document.createElementNS("http://www.w3.org/2000/svg", "path");
     arrow.setAttribute("d", "M 0 0 L 10 5 L 0 10 z");
-    arrow.setAttribute("fill", "#4a5560");
+    arrow.setAttribute("fill", BOUNDARY_LINE_COLOR);
     marker.append(arrow);
     definitions.append(marker);
     svg.append(definitions);
@@ -484,9 +486,7 @@ export class CmapItemDecorator {
         (Number(crossing.insideConcept.node.attr("width")) / 2);
       const insideY = Number(crossing.insideConcept.node.attr("y")) +
         (Number(crossing.insideConcept.node.attr("height")) / 2);
-      const outsideX = Number(crossing.outsideConcept.node.attr("x")) +
-        (Number(crossing.outsideConcept.node.attr("width")) / 2);
-      const side = outsideX < insideX ? "left" : "right";
+      const side = insideX <= viewLeft + (viewWidth / 2) ? "left" : "right";
       const x = side === "left" ? viewLeft + 12 : viewLeft + viewWidth - buttonWidth - 12;
       const y = reserveY(side, insideY - 15);
       const button = document.createElement("button");
@@ -512,7 +512,7 @@ export class CmapItemDecorator {
       const endY = crossing.sourceInside ? boundaryY : insideY;
       path.setAttribute("d", `M ${startX} ${startY} L ${endX} ${endY}`);
       path.setAttribute("fill", "none");
-      path.setAttribute("stroke", crossing.connector.lineColor || "#4a5560");
+      path.setAttribute("stroke", BOUNDARY_LINE_COLOR);
       path.setAttribute("stroke-width", String(crossing.connector.lineWidth || 2));
       if (crossing.connector.hasArrow) path.setAttribute("marker-end", "url(#rw-cmap-boundary-arrow)");
       svg.append(path);
diff --git a/static/index.html b/static/index.html
index 8bfe559..97d8ccc 100644
--- a/static/index.html
+++ b/static/index.html
@@ -147,7 +147,7 @@
       <section id="cmap-view" class="hidden">
         <header class="cmap-page-header">
           <div class="cmap-storage-controls">
-            <span id="cmap-map-navigation" class="cmap-map-navigation hidden"><button id="cmap-map-back" type="button" aria-label="Back to parent map">←</button><strong id="cmap-active-map-title"></strong></span>
+            <span id="cmap-map-navigation" class="cmap-map-navigation hidden"><strong id="cmap-active-map-title"></strong></span>
             <div id="cmap-map-combobox" class="wiki-combobox">
               <input id="cmap-map-select" type="search" role="combobox"
                      aria-label="Concept map" data-tr-placeholder="select-concept-map"
diff --git a/static/js/wiki/cmap/workspace.js b/static/js/wiki/cmap/workspace.js
index a779e39..048fc6d 100644
--- a/static/js/wiki/cmap/workspace.js
+++ b/static/js/wiki/cmap/workspace.js
@@ -776,12 +776,7 @@ export class CmapWorkspace {
             navigateToHash(cmapRoute(record.cmapSlug)).catch((error) => console.error(error));
           }
         },
-        onOpenBoundaryReference: () => {
-          const source = state.currentConceptMapSource;
-          if (source) {
-            navigateToHash(cmapRoute(source.slug)).catch((error) => console.error(error));
-          }
-        },
+        onOpenBoundaryReference: () => openParentCmap(),
         onOpenSubMap: (record) => {
           console.info("[racket-wiki:cmap-host 0.2.122] submap state changed", {
             id: record.id,
@@ -1713,20 +1708,6 @@ export class CmapWorkspace {
         markCurrentCmapSaved();
       }
     });
-    const navigateToParentCmap = () => {
-      const prototype = cmapPrototypeState();
-      if (prototype.editor && prototype.editor.canStepBackWithinMap()) {
-        prototype.editor.openParentMap();
-        return;
-      }
-      if (state.currentConceptMapSource) {
-        navigateToHash(cmapRoute(state.currentConceptMapSource.slug))
-          .catch((error) => console.error(error));
-        return;
-      }
-      if (prototype.editor) prototype.editor.openParentMap();
-    };
-    $("cmap-map-navigation").addEventListener("click", navigateToParentCmap);
     $("cmap-canvas").addEventListener("contextmenu", (event) => {
       event.preventDefault();
       const prototype = cmapPrototypeState();
diff --git a/test/cmap-connector-rewire.test.js b/test/cmap-connector-rewire.test.js
index 7a1ea88..16f8ab1 100644
--- a/test/cmap-connector-rewire.test.js
+++ b/test/cmap-connector-rewire.test.js
@@ -218,3 +218,34 @@ test("moving a concept also moves connected concepts that link to another CMap",
     linked: [500, 140]
   });
 });
+
+test("moving a concept schedules one boundary-reference geometry refresh", async () => {
+  const factory = await loadEditorFactory();
+  const frames = [];
+  global.window.requestAnimationFrame = (callback) => frames.push(callback);
+  const map = {
+    onSelection() {},
+    onActivation() {},
+    node: (attributes) => fakeNode(attributes)
+  };
+  const canvas = {
+    addEventListener() {},
+    querySelector: () => null,
+    clientWidth: 1200,
+    clientHeight: 800,
+    scrollLeft: 0,
+    scrollTop: 0,
+    isConnected: true
+  };
+  const editor = factory.createEditor(canvas, { createDiagramEngine: () => map });
+  const concept = editor.addItem({ id: 1, label: "Inside concept", x: 100, y: 100 });
+  let refreshCount = 0;
+  editor.refreshBoundaryReferences = () => { refreshCount += 1; };
+
+  editor.handleItemMove(concept, 150, 130);
+  editor.handleItemMove(concept, 170, 140);
+
+  assert.equal(frames.length, 1, "pointer moves in one frame are coalesced");
+  frames[0]();
+  assert.equal(refreshCount, 1);
+});