diff --git a/src/app/view.rs b/src/app/view.rs
index 867cdd635..58712e8fe 100644
--- a/src/app/view.rs
+++ b/src/app/view.rs
@@ -457,61 +457,22 @@ impl H7CAD {
 
 // ── Paper canvas ──────────────────────────────────────────────────────────
 //
-// In paper space, the main canvas is composed of:
-//   1. A full-size PaperSheet layer — renders paper-space entities (title blocks,
-//      frames, borders) with the paper-space camera.
-//   2. One ViewportPane::Paper widget per Viewport entity, positioned at its
-//      paper-space coordinates and sized to its paper-space dimensions.
-//      Each renders model-space content through its own viewport camera.
-//   3. The existing selection_overlay / viewport_mouse / nav stack on top
-//      (unchanged — mouse event routing stays the same).
+// Renders the full paper canvas as a single full-size shader widget using the
+// PaperSheet mode, which includes both paper-space entities (title blocks,
+// frames, borders) and model-space content projected through each viewport's
+// view matrix into paper-space coordinates.
+//
+// Note: A per-viewport widget approach (ViewportPane::Paper) was attempted but
+// does not work correctly because Iced 0.14 batches all shader prepare() calls
+// before any render() calls, causing widgets that share the same Pipeline type
+// to overwrite each other's GPU buffers. The CPU-projection approach used here
+// is the correct solution within Iced's shader framework.
 
 fn paper_canvas_view<'a>(tab: &'a super::document::DocumentTab) -> Element<'a, Message> {
-    let scene = &tab.scene;
-
-    // Layer 1: paper-space entities (title blocks, frames, paper boundary).
-    let paper_sheet = shader(ViewportPane::paper_sheet(scene))
+    shader(ViewportPane::paper_sheet(&tab.scene))
         .width(Fill)
-        .height(Fill);
-
-    // Use the last-rendered canvas size to compute pixel positions.
-    // On the very first frame this is (0,0); correct positions appear from
-    // the second frame onward (imperceptible in practice).
-    let (canvas_w, canvas_h) = scene.selection.borrow().vp_size;
-    let vp_list = scene.viewport_list();
-
-    let mut layers = stack![paper_sheet];
-
-    for (handle, _, _) in &vp_list {
-        let Some(rect) = scene.viewport_screen_rect(*handle, (canvas_w, canvas_h)) else {
-            continue;
-        };
-
-        // Clamp to avoid zero-size or negative widgets.
-        let w = rect.width.max(1.0);
-        let h = rect.height.max(1.0);
-        let x = rect.x.max(0.0);
-        let y = rect.y.max(0.0);
-
-        // Layer 2+: one shader widget per viewport, positioned with Space offsets.
-        let vp_widget = shader(ViewportPane::paper(scene, *handle))
-            .width(iced::Length::Fixed(w))
-            .height(iced::Length::Fixed(h));
-
-        let positioned = column![
-            Space::new().height(iced::Length::Fixed(y)),
-            row![
-                Space::new().width(iced::Length::Fixed(x)),
-                vp_widget,
-            ],
-        ]
-        .width(Fill)
-        .height(Fill);
-
-        layers = layers.push(positioned);
-    }
-
-    layers.width(Fill).height(Fill).into()
+        .height(Fill)
+        .into()
 }
 
 // ── Document tab bar ───────────────────────────────────────────────────────
diff --git a/src/scene/mod.rs b/src/scene/mod.rs
index 22286c268..39ffef8d3 100644
--- a/src/scene/mod.rs
+++ b/src/scene/mod.rs
@@ -2103,9 +2103,9 @@ impl Scene {
     /// `Rectangle` relative to the top-left of the paper canvas.
     ///
     /// `canvas_px`  — the pixel dimensions of the area that shows the paper.
-    /// Paper limits from the current layout define the paper-space extent;
-    /// the viewport is mapped linearly into that area (Y-axis flipped).
-    /// Returns `None` if the viewport handle is invalid or paper limits are missing.
+    /// Map a paper-space viewport into screen-pixel coordinates.
+    /// Needed when per-viewport shader widgets are revived (see `ViewportPaneMode::Paper`).
+    #[allow(dead_code)]
     pub fn viewport_screen_rect(
         &self,
         vp_handle: Handle,
diff --git a/src/scene/render.rs b/src/scene/render.rs
index 31a8abdbc..bc14f3b24 100644
--- a/src/scene/render.rs
+++ b/src/scene/render.rs
@@ -196,10 +196,9 @@ impl Scene {
         }
     }
 
-    /// Build a Primitive for the paper-sheet background: paper-space entities
-    /// (title blocks, frames, borders) using the paper-space camera.
-    /// Viewport content is NOT included — it is rendered by separate
-    /// `ViewportPane::Paper` widgets stacked on top.
+    /// Build a Primitive for the full paper canvas: paper-space entities
+    /// (title blocks, frames, borders) plus model-space content projected
+    /// through each viewport's view matrix into paper-space coordinates.
     pub(super) fn build_paper_sheet_primitive(
         &self,
         hover_region: Option<usize>,
@@ -208,7 +207,9 @@ impl Scene {
         let cam = self.camera.borrow();
         self.selection.borrow_mut().vp_size = (bounds.width, bounds.height);
 
+        let layout_block = self.current_layout_block_handle();
         let mut wires = self.paper_sheet_wires();
+        wires.extend(self.viewport_content_wires(layout_block, None));
         if let Some(iw) = &self.interim_wire {
             wires.push(iw.clone());
         }
diff --git a/src/scene/viewport_pane.rs b/src/scene/viewport_pane.rs
index d436b1c49..20a8cc056 100644
--- a/src/scene/viewport_pane.rs
+++ b/src/scene/viewport_pane.rs
@@ -9,10 +9,17 @@ use iced::{mouse, Event, Rectangle};
 pub enum ViewportPaneMode {
     /// Full model space — fills whatever bounds Iced assigns.
     Model,
-    /// Paper-space entities only (title blocks, frames, borders) using the
-    /// paper-space camera. No viewport content projection.
+    /// Paper-space entities plus model content projected through viewports.
+    /// Used for the full paper canvas (single widget, no per-viewport widgets).
     PaperSheet,
-    /// Model-space content seen through a specific paper-space Viewport entity.
+    /// Model-space content rendered through a specific viewport's 3-D camera.
+    ///
+    /// NOTE: Currently unused because Iced 0.14 batches all shader `prepare()`
+    /// calls before any `render()` calls. Multiple widgets sharing the same
+    /// `Pipeline` type overwrite each other's GPU buffers.  A per-viewport
+    /// wgpu sub-renderer that accumulates data across frames would be needed to
+    /// revive this path.
+    #[allow(dead_code)]
     Paper { handle: Handle },
 }
 
@@ -34,6 +41,8 @@ impl<'a> ViewportPane<'a> {
     }
 
     /// One paper-space viewport: model content rendered through its own camera.
+    /// See [`ViewportPaneMode::Paper`] for why this is currently unused.
+    #[allow(dead_code)]
     pub fn paper(scene: &'a Scene, handle: Handle) -> Self {
         Self { scene, mode: ViewportPaneMode::Paper { handle } }
     }