diff --git a/plugin-designs/my-upg-100-list/poster-wall.vue b/plugin-designs/my-upg-100-list/poster-wall.vue
index 66b565cd6..f9f73a1a7 100644
--- a/plugin-designs/my-upg-100-list/poster-wall.vue
+++ b/plugin-designs/my-upg-100-list/poster-wall.vue
@@ -274,38 +274,69 @@ const { scrimRef, scrimStyle } = useViewportScrim(exportState)
 // all stay — printPoster below still uses posterUrl(), and all three print paths still
 // share the exportState HUD for progress/errors.
 
-// ─── SHARED PRINT-WINDOW MECHANISM ────────────────────────────────────────────
+// ─── SHARED PRINT MECHANISM ───────────────────────────────────────────────────
 // ONE mechanism, reused by all three "Print …" actions (poster / list / card
-// deck) rather than three ad-hoc window.opens. Extracted from the poster path,
-// which already carries the load-bearing fix documented below.
-//
-// ★ NO `noopener` HERE, AND THAT IS THE WHOLE FIX (2026-09-23). `noopener` makes window.open()
-// return null BY SPECIFICATION — severing the opener relationship is exactly what the flag does,
-// so there is no handle to hand back. With it, `w` was always null, the document.write preview
-// below was UNREACHABLE FOR EVERY USER, and every click fell through to a raw-content fallback.
-// MEASURED in a default (non-headless-flagged) browser: window.open('','_blank','noopener') -> null,
-// the identical call without the flag -> a usable handle. I first attributed the null to this
-// headless box; it is not environmental, it is what the flag means.
-// The window we write into carries same-origin markup we generate ourselves, so the opener
-// reference it regains is our own — there is nothing hostile for `noopener` to protect against here.
+// deck) rather than three ad-hoc implementations.
 //
 // `bodyHtml` is the FULL <html> document string (caller owns <head>/<style>/<body>). The caller's
 // content is responsible for its own print trigger — pass `autoprint:true` to have this helper
 // append the `window.focus();window.print()` bootstrap (used by markup with no <img onload> of
 // its own to hang the call off).
+//
+// ── HISTORY, kept because the lesson outlives the code that taught it ──
+// This helper used to call window.open(). An earlier build passed `noopener`, which makes
+// window.open() return null BY SPECIFICATION — severing the opener relationship is exactly what
+// the flag does, so there was no handle to write into. Every click silently fell through to a
+// raw-content fallback, for every user. MEASURED: window.open('','_blank','noopener') -> null;
+// the identical call without the flag -> a usable handle. It was first blamed on the headless box;
+// it was not environmental, it was what the flag means.
+// The iframe below makes that class of failure unreachable — there is no popup to block and no
+// opener flag to get wrong — but the lesson stands: a flag that returns null by spec will look
+// exactly like an environment problem.
+// ★ IN-PLACE (2026-09-23) — a hidden same-page IFRAME, not a popup window.
+//
+// WHY THIS CHANGED, so nobody "restores" the popup as a regression fix: an EARLIER Driver ask
+// wanted a preview window ("show the poster in your browser to help you print it"), and this
+// helper was built around window.open() to serve it. The Driver has now REVERSED that: the print
+// dialog must open DIRECTLY, with no second browser window. That is a decision change, not a bug.
+//
+// An iframe is the right vehicle because it keeps the ENTIRE existing contract: callers still pass
+// one full <html> document string, we still document.write() it, and the markup's own
+// `<img onload> -> window.print()` still fires — only now `window` inside that document is the
+// iframe's contentWindow, so the dialog belongs to THIS page. All three print paths (poster /
+// list / card deck) stay on this one mechanism.
+//
+// It also deletes a whole failure mode: there is no popup blocker on an iframe, so the
+// "popup blocked -> fall back to opening the raw image" branch every caller carried is now dead.
+// The returned object keeps a truthy `.document`-less shape only so existing `if (!w)` guards stay
+// harmless; callers should no longer rely on a popup-blocked null.
 function openPrintWindow(title, bodyHtml, { autoprint = false } = {}) {
-  const w = window.open('', '_blank', 'width=980,height=1100')
-  if (!w) return null                                   // popup blocked — caller decides the fallback
-  w.document.open()
-  w.document.write(bodyHtml)
+  const frame = document.createElement('iframe')
+  // Off-screen rather than display:none — a display:none iframe does not lay out in every engine,
+  // and a zero-height layout can print a blank first page.
+  frame.setAttribute('aria-hidden', 'true')
+  frame.style.cssText = 'position:fixed;right:0;bottom:0;width:1px;height:1px;opacity:0;border:0'
+  document.body.appendChild(frame)
+
+  const doc = frame.contentDocument
+  if (!doc) { frame.remove(); return null }             // no document -> caller keeps its fallback
+  doc.open()
+  doc.write(bodyHtml)
   if (autoprint) {
     // Appended AFTER the caller's markup so it runs once the document is parsed —
     // matches the <img onload> timing the poster path already relies on.
-    w.document.write(
+    doc.write(
       '<script>window.addEventListener("load",function(){setTimeout(function(){window.focus();window.print()},150)})</' + 'script>')
   }
-  w.document.close()
-  return w
+  doc.close()
+
+  // Reclaim the node once the dialog has been dismissed. `afterprint` is the honest signal; the
+  // timeout is a floor for engines that never fire it, so a click can never leak a frame per press.
+  const drop = () => { if (frame.parentNode) frame.remove() }
+  try { frame.contentWindow.addEventListener('afterprint', () => setTimeout(drop, 0)) } catch { /* cross-doc guard */ }
+  setTimeout(drop, 60000)
+
+  return frame.contentWindow
 }
 
 // Escape the handful of characters that break out of an HTML text node or a "..." attribute.
@@ -336,20 +367,33 @@ async function printPoster(list) {
     const title = `Doxa UPG-100 poster — ${escapeHtml(list.label || list.id)}`
     const w = openPrintWindow(title,
       '<!DOCTYPE html><html><head><meta charset="utf-8"><title>' + title + '</title>' +
-      '<style>@page{size:auto;margin:12mm}html,body{margin:0;height:100%;background:#fff}' +
+      // PORTRAIT, explicitly. `size:auto` let the browser choose, and it chooses LANDSCAPE for a
+      // square: the poster art is 3ft x 3ft (aspect-ratio:1/1, see the wall template below), so an
+      // auto page has no reason to prefer the tall axis. The list and card-deck print paths in this
+      // same file already pin `size:letter portrait`; the poster path was the odd one out.
+      // (Driver: "print to a vertical piece of printer paper".)
+      '<style>@page{size:letter portrait;margin:12mm}html,body{margin:0;height:100%;background:#fff}' +
       'body{display:flex;align-items:center;justify-content:center}' +
       'img{max-width:100%;max-height:100vh;object-fit:contain;display:block}' +
-      '@media print{body{height:auto}img{max-height:none;width:100%}}</style></head>' +
+      // A SQUARE on a PORTRAIT sheet must fit by its SHORTER axis. The old print rule
+      // (`max-height:none;width:100%`) scaled the square to the full page WIDTH, which on portrait
+      // letter is taller than the printable height -> the poster overflowed onto a second page.
+      // Constrain BOTH axes and let object-fit letterbox it inside the sheet instead.
+      '@media print{body{height:auto}' +
+      'img{width:auto;max-width:100%;max-height:100%;object-fit:contain}}</style></head>' +
       '<body><img src="' + url + '" alt="' + title + '"' +
       ' onload="setTimeout(function(){window.focus();window.print()},150)"' +
       ' onerror="document.body.innerHTML=\'<p style=&quot;font:16px system-ui;padding:24px&quot;>Poster not available yet.</p>\'">' +
       '</body></html>')
-    if (!w) {                                          // popup blocked → open the image tab
+    if (!w) {
+      // No longer "popup blocked" — an iframe cannot be blocked. This is now only reachable if the
+      // frame has no contentDocument at all (a sandboxed/detached host), so the honest fallback is
+      // the poster itself rather than a pop-up instruction the user cannot act on.
       window.open(url, '_blank', 'noopener')
       exportState.value = { ...exportState.value, phase: 'done', message: 'opened poster', pct: 100 }
       setTimeout(() => { exportState.value = null }, 900); return
     }
-    exportState.value = { ...exportState.value, phase: 'done', message: 'print preview opened', pct: 100 }
+    exportState.value = { ...exportState.value, phase: 'done', message: 'print dialog opened', pct: 100 }
     setTimeout(() => { exportState.value = null }, 900)
   } catch (e) {
     exportState.value = { label: list.label, kind: 'Poster', phase: 'error',
@@ -433,11 +477,13 @@ async function printList100(list) {
       '<th>Religion</th><th></th></tr></thead><tbody>' + rowsHtml + '</tbody></table>' +
       '</body></html>', { autoprint: true })
     if (!w) {
+      // Not a pop-up blocker any more (this prints via a same-page iframe). Only a host that
+      // denies us a contentDocument lands here, so say something the user can act on.
       exportState.value = { label: list.label, kind: 'UPG-100 List', phase: 'error',
-        message: 'Pop-up blocked — allow pop-ups for this site and try again.', pct: 0 }
+        message: 'Could not open the print dialog in this view — try the Download button.', pct: 0 }
       return
     }
-    exportState.value = { ...exportState.value, phase: 'done', message: 'print preview opened', pct: 100 }
+    exportState.value = { ...exportState.value, phase: 'done', message: 'print dialog opened', pct: 100 }
     setTimeout(() => { exportState.value = null }, 900)
   } catch (e) {
     exportState.value = { label: list.label, kind: 'UPG-100 List', phase: 'error',
@@ -505,11 +551,12 @@ async function printCardDeck(list) {
       '<div class="deck">' + cardsHtml + '</div>' +
       '</body></html>', { autoprint: true })
     if (!w) {
+      // See the note in the list path: an iframe cannot be pop-up blocked.
       exportState.value = { label: list.label, kind: 'Card Deck', phase: 'error',
-        message: 'Pop-up blocked — allow pop-ups for this site and try again.', pct: 0 }
+        message: 'Could not open the print dialog in this view — try the Download button.', pct: 0 }
       return
     }
-    exportState.value = { ...exportState.value, phase: 'done', message: 'print preview opened', pct: 100 }
+    exportState.value = { ...exportState.value, phase: 'done', message: 'print dialog opened', pct: 100 }
     setTimeout(() => { exportState.value = null }, 900)
   } catch (e) {
     exportState.value = { label: list.label, kind: 'Card Deck', phase: 'error',