diff --git a/docker/frontend/src/Library.tsx b/docker/frontend/src/Library.tsx
index 2c6151c..7ff4fa3 100644
--- a/docker/frontend/src/Library.tsx
+++ b/docker/frontend/src/Library.tsx
@@ -4404,16 +4404,29 @@ function useStripWindow(count: number, on: boolean): { ref: RefObject<HTMLDivEle
 // longer has is a row that runs past the wall or stops short of it.
 function useWallWidth(ref: RefObject<HTMLDivElement>, on: boolean): number {
   const [width, setWidth] = useState(0);
+  // Read off the wall that is up and not off the one this was set up on: the wall
+  // is what the desk draws, and the phone's shelf stands in its place, so a visit
+  // that opens on the phone mounts it with no wall to measure — and the width left
+  // at nought lays every row of the shelf out one pixel wide, which is a wall of
+  // nothing until something else makes the effect below run again. So it is read
+  // after every render, the way the window the wall draws is (see `useWallWindow`).
+  const read = useCallback(() => {
+    const el = ref.current;
+    if (!el || !el.clientWidth) return;
+    setWidth((prev) => (prev === el.clientWidth ? prev : el.clientWidth));
+  }, [ref]);
+  useLayoutEffect(() => {
+    read();
+  });
   useLayoutEffect(() => {
     if (!on) return;
+    read();
     const el = ref.current;
     if (!el) return;
-    const read = () => setWidth((prev) => (prev === el.clientWidth ? prev : el.clientWidth));
-    read();
     const ro = new ResizeObserver(read);
     ro.observe(el);
     return () => ro.disconnect();
-  }, [ref, on]);
+  }, [ref, on, read]);
   return width;
 }