diff --git a/src/components/tools/polygon/PolygonTool.vue b/src/components/tools/polygon/PolygonTool.vue
index 1d1134ce..7153760e 100644
--- a/src/components/tools/polygon/PolygonTool.vue
+++ b/src/components/tools/polygon/PolygonTool.vue
@@ -54,6 +54,7 @@ import {
 import AnnotationContextMenu from '@/src/components/tools/AnnotationContextMenu.vue';
 import AnnotationInfo from '@/src/components/tools/AnnotationInfo.vue';
 import { useFrameOfReference } from '@/src/composables/useFrameOfReference';
+import { actionToKey } from '@/src/composables/useKeyboardShortcuts';
 import { Maybe } from '@/src/types';
 import { useSliceInfo } from '@/src/composables/useSliceInfo';
 import { useMagicKeys, watchImmediate } from '@vueuse/core';
@@ -126,7 +127,11 @@ export default defineComponent({
       placingTool.remove();
     });
 
-    const { v: mergeKey } = useMagicKeys();
+    const keys = useMagicKeys();
+    const mergeKey = computed(
+      () => keys[actionToKey.value.mergeNewPolygon].value
+    );
+
     const onToolPlaced = () => {
       if (imageId.value) {
         const newToolId = placingTool.id.value;
diff --git a/src/composables/actions.ts b/src/composables/actions.ts
index d481aa4d..99660b60 100644
--- a/src/composables/actions.ts
+++ b/src/composables/actions.ts
@@ -51,5 +51,7 @@ export const ACTION_TO_FUNC = {
   decrementLabel: applyLabelOffset(-1),
   incrementLabel: applyLabelOffset(1),
 
+  mergeNewPolygon: () => {}, // acts as a modifier key rather than immediate effect, so no-op
+
   showKeyboardShortcuts,
 } as const satisfies Record<Action, () => void>;
diff --git a/src/config.ts b/src/config.ts
index fb564eee..67fdc478 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -296,6 +296,7 @@ export const ACTION_TO_KEY = {
   crosshairs: 'c',
   crop: 'b',
   polygon: 'g',
+  mergeNewPolygon: 'g',
   select: 's',
 
   decrementLabel: 'q',
diff --git a/src/constants.ts b/src/constants.ts
index 8212207b..ebc62ce1 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -60,6 +60,10 @@ export const ACTIONS = {
     readable: 'Activate next Label',
   },
 
+  mergeNewPolygon: {
+    readable: 'Hold down to merge new polygons with overlapping polygons',
+  },
+
   showKeyboardShortcuts: {
     readable: 'Show keyboard shortcuts dialog',
   },
diff --git a/src/store/tools/polygons.ts b/src/store/tools/polygons.ts
index 2a3f292c..a3e48f74 100644
--- a/src/store/tools/polygons.ts
+++ b/src/store/tools/polygons.ts
@@ -1,4 +1,4 @@
-import * as polygonClipping from 'polyclip-ts';
+import { intersection, union, Geom } from 'polyclip-ts';
 import type { Vector3 } from '@kitware/vtk.js/types';
 import { computed } from 'vue';
 import {
@@ -42,7 +42,7 @@ export const usePolygonStore = defineAnnotationToolStore('polygon', () => {
   const polygonsOverlap = (a: Tool, b: Tool) => {
     const [aGeo, bGeo] = [a, b].map(toGeoJSON);
     if (!aGeo || !bGeo) return false;
-    return polygonClipping.intersection(aGeo, bGeo).length > 0;
+    return intersection(aGeo, bGeo).length > 0;
   };
 
   const sameSliceAndLabel = (a: Tool, b: Tool) =>
@@ -82,14 +82,13 @@ export const usePolygonStore = defineAnnotationToolStore('polygon', () => {
   });
 
   function mergeToolGroup(mergeGroup: Tool[]) {
-    const firstTool = mergeGroup[0];
-
     const polygons = mergeGroup.map(toGeoJSON);
     if (polygons.some((p) => !p))
       throw new Error('Trying to merge invalid polygons');
 
-    const [first, ...rest] = polygons as unknown as polygonClipping.Geom[];
-    const merged = polygonClipping.union(first, ...rest);
+    const [first, ...rest] = polygons as unknown as Geom[];
+    const merged = union(first, ...rest);
+    const firstTool = mergeGroup[0];
     const { to3D } = getPlaneTransforms(firstTool.frameOfReference);
     const points = merged.flatMap((p) => p.flatMap((ring) => ring.map(to3D)));