diff --git a/src/components/Viewfinder.tsx b/src/components/Viewfinder.tsx
index 8afc95f..2b84ee9 100644
--- a/src/components/Viewfinder.tsx
+++ b/src/components/Viewfinder.tsx
@@ -975,6 +975,15 @@ const Viewfinder = forwardRef<ViewfinderHandle, ViewfinderProps>(function Viewfi
   // point / double-tap again to reset to 100%. Transform is a Skia matrix
   // P' = scale*P + (tx,ty); gesture math keeps the focal point stationary.
   const [libZoom, setLibZoom] = useState({ s: 1, tx: 0, ty: 0 });
+  // The mark editor works in the UN-zoomed composition: a photo zoom left over
+  // from the panel-closed pass (zoom in to check a slider, then come back to
+  // WATERMARK) shifted the mark's hit box with the matrix AND tripped the
+  // `libZoom.s <= 1.01` guards, so the mark could neither be dragged nor
+  // pinched. Opening the editor therefore drops the photo zoom.
+  useEffect(() => {
+    if (wmEditing) setLibZoom((z) => (z.s <= 1.001 ? z : { s: 1, tx: 0, ty: 0 }));
+  }, [wmEditing]);
+
   const pinchRef = useRef<{ d: number; s: number; tx: number; ty: number; fx: number; fy: number } | null>(null);
   const pinchUsedRef = useRef(false);
   // Framed-window drag: anchor at touch-down (finger + transform origin), so a
@@ -1054,6 +1063,32 @@ const Viewfinder = forwardRef<ViewfinderHandle, ViewfinderProps>(function Viewfi
     if (selectedFrame === 'wallframe' && wallGeo && wallImage) return wallGeo.window;
     return null;
   };
+  // Framed photo windows move when the deck grows (slider) or shrinks: the
+  // photo content is scaled about its own top-left, so a plain move of the
+  // window under a zoomed photo slides the visible crop away from the card.
+  // Re-anchor the transform when the window rect changes so the SAME part of
+  // the photo stays inside the frame (same u/v math the export uses).
+  const winRectRef = useRef<{ x: number; y: number; w: number; h: number } | null>(null);
+  useEffect(() => {
+    const win = zoomWindowRect();
+    const prev = winRectRef.current;
+    winRectRef.current = win ? { ...win } : null;
+    if (!prev || !win) return;
+    if (prev.x === win.x && prev.y === win.y && prev.w === win.w && prev.h === win.h) return;
+    setLibZoom((z) => {
+      if (z.s <= 1.001) return z;
+      const tlx = z.tx + (z.s - 1) * prev.x;
+      const tly = z.ty + (z.s - 1) * prev.y;
+      const u = (prev.w / 2 - tlx) / (z.s * prev.w);
+      const v = (prev.h / 2 - tly) / (z.s * prev.h);
+      return {
+        s: z.s,
+        tx: win.w / 2 - u * z.s * win.w - (z.s - 1) * win.x,
+        ty: win.h / 2 - v * z.s * win.h - (z.s - 1) * win.y,
+      };
+    });
+  });
+
   // Clamp pan/zoom so the photo always keeps COVERING the framed window (never
   // drags far enough to reveal the card/mat through the transparent opening).
   // Transform is P' = s*P + t in canvas coords; with the photo drawn over the