diff --git a/app/web/static/compare.js b/app/web/static/compare.js
index 9fefffd..6b808bd 100644
--- a/app/web/static/compare.js
+++ b/app/web/static/compare.js
@@ -1,7 +1,7 @@
 // compare.js — thin shim that parses ?stem=…&stem=… (legacy ?a=&b=) and
 // hands off to panel-grid.js.
 
-import { mountPanels } from './panel-grid.js?v=4';
+import { mountPanels } from './panel-grid.js?v=5';
 
 const params = new URLSearchParams(window.location.search);
 let stems = params.getAll('stem').filter(Boolean);
diff --git a/app/web/static/panel-grid.js b/app/web/static/panel-grid.js
index 194819f..ee67a19 100644
--- a/app/web/static/panel-grid.js
+++ b/app/web/static/panel-grid.js
@@ -713,18 +713,33 @@ export function mountPanels({ host, controls, stems }) {
     if (colorSel) onCtl(colorSel, 'change', applyColorMode);
     applyColorMode();
 
-    // Linked hover across every panel.
+    // Linked hover + click-to-pin. Hover shows the point under the cursor
+    // across all panels. Click toggles a "pinned" id that stays highlighted
+    // once the cursor leaves; hover temporarily overrides the display.
+    let pinnedId = null;
+    let hoveredId = null;
+    function paintHighlight() {
+      const id = hoveredId !== null ? hoveredId : pinnedId;
+      for (const t of live) t.panel.setHighlight(id);
+    }
     for (const s of live) {
       const mm = (ev) => {
         const id = s.panel.pickAt(ev.clientX, ev.clientY);
-        const hid = id >= 0 ? id : null;
-        for (const t of live) t.panel.setHighlight(hid);
+        hoveredId = id >= 0 ? id : null;
+        paintHighlight();
+      };
+      const ml = () => { hoveredId = null; paintHighlight(); };
+      const mc = (ev) => {
+        const id = s.panel.pickAt(ev.clientX, ev.clientY);
+        pinnedId = (id < 0 || id === pinnedId) ? null : id;
+        paintHighlight();
       };
-      const ml = () => { for (const t of live) t.panel.setHighlight(null); };
       s.panel.canvasEl.addEventListener('mousemove', mm);
       s.panel.canvasEl.addEventListener('mouseleave', ml);
+      s.panel.canvasEl.addEventListener('click', mc);
       listeners.push({ el: s.panel.canvasEl, ev: 'mousemove', fn: mm });
       listeners.push({ el: s.panel.canvasEl, ev: 'mouseleave', fn: ml });
+      listeners.push({ el: s.panel.canvasEl, ev: 'click', fn: mc });
     }
 
     // Resize + theme observers.
diff --git a/app/web/static/run-modal.js b/app/web/static/run-modal.js
index c996d0a..29b0b39 100644
--- a/app/web/static/run-modal.js
+++ b/app/web/static/run-modal.js
@@ -1,7 +1,7 @@
 // run-modal.js — homepage click-hijack for embedding links. Opens a
 // <dialog id="run-modal"> that renders the run's embedding via panel-grid.js.
 
-import { mountPanels } from './panel-grid.js?v=4';
+import { mountPanels } from './panel-grid.js?v=5';
 
 const dialog = document.getElementById('run-modal');
 const host = document.getElementById('modal-panel-host');
diff --git a/app/web/static/style.css b/app/web/static/style.css
index f23461d..b070979 100644
--- a/app/web/static/style.css
+++ b/app/web/static/style.css
@@ -1594,6 +1594,7 @@ button.submit:disabled { background: var(--faint); border-color: var(--faint); c
      axes dropdown via --canvas-aspect on the grid. --panel-h is the cap. */
   aspect-ratio: var(--canvas-aspect, 1 / 1);
   max-height: var(--panel-h);
+  cursor: crosshair;
 }
 
 .compare-canvas canvas {
diff --git a/app/web/templates/compare.html b/app/web/templates/compare.html
index f9ec60b..8746396 100644
--- a/app/web/templates/compare.html
+++ b/app/web/templates/compare.html
@@ -4,7 +4,7 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width,initial-scale=1" />
   <title>embedding notebook &middot; compare</title>
-  <link rel="stylesheet" href="/static/style.css?v=31" />
+  <link rel="stylesheet" href="/static/style.css?v=32" />
   <script type="importmap">
   {
     "imports": {
@@ -102,7 +102,7 @@
 </template>
 
 <script src="/static/theme.js?v=11"></script>
-<script type="module" src="/static/compare.js?v=16"></script>
+<script type="module" src="/static/compare.js?v=17"></script>
 <!-- panel-grid.js is imported by compare.js (module); versioned via compare.js cache-bust -->
 
 </body>
diff --git a/app/web/templates/index.html b/app/web/templates/index.html
index 7bf6295..0fc1169 100644
--- a/app/web/templates/index.html
+++ b/app/web/templates/index.html
@@ -4,7 +4,7 @@
   <meta charset="utf-8" />
   <meta name="viewport" content="width=device-width,initial-scale=1" />
   <title>embedding notebook</title>
-  <link rel="stylesheet" href="/static/style.css?v=31" />
+  <link rel="stylesheet" href="/static/style.css?v=32" />
   <script src="https://unpkg.com/htmx.org@2.0.4"></script>
   <script type="importmap">
   {