diff --git a/Python/05_Results_Visualization.ipynb b/Python/05_Results_Visualization.ipynb
index b63e49bb..d44b3fdf 100644
--- a/Python/05_Results_Visualization.ipynb
+++ b/Python/05_Results_Visualization.ipynb
@@ -1085,33 +1085,27 @@
     "    for c in colors:\n",
     "        if c == [0, 0, 0]:\n",
     "            raise ValueError(\"Colors include black [0,0,0], not allowed\")\n",
-    "    empty_image = image * 0\n",
-    "    overlay_boundaries = [\n",
-    "        sitk.LabelMapContourOverlay(\n",
-    "            sitk.Cast(seg, sitk.sitkLabelUInt8),\n",
-    "            empty_image,\n",
-    "            opacity=1,\n",
-    "            contourThickness=thickness,\n",
-    "            dilationRadius=dilation_radius,\n",
-    "            colormap=color,\n",
-    "        )\n",
-    "        for seg, color in zip(binary_segmentations, colors)\n",
+    "\n",
+    "    # Merge into a single label map (MergeLabelMapFilter's default KEEP method\n",
+    "    # keeps each input's region distinct even though they all use label 1),\n",
+    "    # so LabelMapContourOverlay handles overlapping contours itself in a\n",
+    "    # single pass instead of manually compositing per-segmentation results.\n",
+    "    merged_labels = sitk.MergeLabelMap(\n",
+    "        [sitk.Cast(seg, sitk.sitkLabelUInt8) for seg in binary_segmentations],\n",
+    "        sitk.MergeLabelMapFilter.Keep,\n",
+    "    )\n",
+    "    flat_colormap = [\n",
+    "        channel for color in colors[: len(binary_segmentations)] for channel in color\n",
     "    ]\n",
     "\n",
-    "    current_image = sitk.Compose([image] * 3)\n",
-    "    for o_image in overlay_boundaries:\n",
-    "        current_mask = (\n",
-    "            sitk.NaryAdd(\n",
-    "                [\n",
-    "                    sitk.VectorIndexSelectionCast(o_image, 0),\n",
-    "                    sitk.VectorIndexSelectionCast(o_image, 1),\n",
-    "                    sitk.VectorIndexSelectionCast(o_image, 2),\n",
-    "                ]\n",
-    "            )\n",
-    "            == 0\n",
-    "        )\n",
-    "        current_image = mask_image_multiply(current_mask, current_image) + o_image\n",
-    "    return current_image\n",
+    "    return sitk.LabelMapContourOverlay(\n",
+    "        merged_labels,\n",
+    "        image,\n",
+    "        opacity=1,\n",
+    "        contourThickness=thickness,\n",
+    "        dilationRadius=dilation_radius,\n",
+    "        colormap=flat_colormap,\n",
+    "    )\n",
     "\n",
     "\n",
     "binary_segmentations = [\n",
diff --git a/tests/additional_dictionary.txt b/tests/additional_dictionary.txt
index c9ff423d..ca4c45a7 100644
--- a/tests/additional_dictionary.txt
+++ b/tests/additional_dictionary.txt
@@ -1,3 +1,5 @@
+LabelMapContourOverlay
+MergeLabelMapFilter's
 ipympl
 ACM
 ANTSNeighborhoodCorrelation