Demo video: show scrolling frames as containers and the flat frame

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -96,8 +96,10 @@ Then open http://localhost:8765/test/ (the cross-origin frame loads from
 
 ## Demo video
 
-[demo/webpad-demo.mp4](demo/webpad-demo.mp4) (≈50 s): D-pad, graph view, stick
-pie, post cards, a scrollable comments panel and cross-origin iframes.
+[demo/webpad-demo.mp4](demo/webpad-demo.mp4) (≈60 s): D-pad, graph view, stick
+pie, post cards, a scrollable comments panel, scrolling iframes (same- and
+cross-origin) as containers, and a non-scrolling iframe whose buttons belong to
+the page.
 
 To re-record (after changes), with the test server running:
 

scripts/record-demo.js

@@ -161,6 +161,12 @@ const SIZE = { width: 1280, height: 720 };
   await press('x', 700); await log('X (enter)');
   await press('ArrowRight', 600); await log('→');
   await press('Enter', 900); await log('A (click in frame)');
+  await press('Backspace', 600); await log('B');
+
+  await section('Iframes', 'text=Left of flat frame', -60);
+  await caption("A frame that doesn't scroll has no stop: its buttons belong to the page");
+  await presses('ArrowRight', 4, 650); await log('→ x4 through the flat frame');
+  await wait(500);
 
   await caption('webpad — D-pad, free-aim stick, cards, scroll panels, iframes');
   await wait(2000);