diff --git a/gfx/layers/composite/APZCTreeManager.cpp b/gfx/layers/composite/APZCTreeManager.cpp
index 11fd90aba662..bc4ddd98f28c 100644
--- a/gfx/layers/composite/APZCTreeManager.cpp
+++ b/gfx/layers/composite/APZCTreeManager.cpp
@@ -134,7 +134,7 @@ APZCTreeManager::UpdatePanZoomControllerTree(CompositorParent* aCompositor,
         controller->NotifyLayersUpdated(container->GetFrameMetrics(),
                                         aIsFirstPaint && (aLayersId == aFirstPaintLayersId));
 
-        LayerRect visible = container->GetFrameMetrics().mViewport * container->GetFrameMetrics().LayersPixelsPerCSSPixel();
+        LayerRect visible = ScreenRect(container->GetFrameMetrics().mCompositionBounds) * ScreenToLayerScale(1.0);
         controller->SetLayerHitTestData(visible, aTransform, aLayer->GetTransform());
         APZC_LOG("Setting rect(%f %f %f %f) as visible region for APZC %p\n", visible.x, visible.y,
                                                                               visible.width, visible.height,
diff --git a/gfx/layers/composite/ContainerLayerComposite.cpp b/gfx/layers/composite/ContainerLayerComposite.cpp
index 70a362065f44..7c67a80285c1 100644
--- a/gfx/layers/composite/ContainerLayerComposite.cpp
+++ b/gfx/layers/composite/ContainerLayerComposite.cpp
@@ -185,8 +185,8 @@ ContainerRender(ContainerT* aContainer,
     ToMatrix4x4(aContainer->GetEffectiveTransform(), transform);
 
     const FrameMetrics& frame = aContainer->GetFrameMetrics();
-    LayerRect layerViewport = frame.mViewport * frame.LayersPixelsPerCSSPixel();
-    gfx::Rect rect(layerViewport.x, layerViewport.y, layerViewport.width, layerViewport.height);
+    LayerRect layerBounds = ScreenRect(frame.mCompositionBounds) * ScreenToLayerScale(1.0);
+    gfx::Rect rect(layerBounds.x, layerBounds.y, layerBounds.width, layerBounds.height);
     gfx::Rect clipRect(aClipRect.x, aClipRect.y, aClipRect.width, aClipRect.height);
     aManager->GetCompositor()->DrawDiagnostics(DIAGNOSTIC_CONTAINER,
                                                rect, clipRect,