diff --git a/packages/autocomplete-js/src/__tests__/api.test.ts b/packages/autocomplete-js/src/__tests__/api.test.ts
index 9bf013ba5..cbf0c05a7 100644
--- a/packages/autocomplete-js/src/__tests__/api.test.ts
+++ b/packages/autocomplete-js/src/__tests__/api.test.ts
@@ -259,6 +259,79 @@ describe('api', () => {
       );
     });
 
+    test('correctly merges DOM Element options', async () => {
+      let inputElement: HTMLInputElement;
+      const onStateChange = jest.fn();
+      const container = document.createElement('div');
+      document.body.appendChild(container);
+      const panelContainer = document.createElement('div');
+      document.body.appendChild(panelContainer);
+      const panelContainer2 = document.createElement('div');
+      document.body.appendChild(panelContainer2);
+
+      const { update } = autocomplete<{ label: string }>({
+        container,
+        onStateChange,
+        panelContainer,
+        shouldPanelOpen: () => true,
+        openOnFocus: true,
+        getSources() {
+          return [
+            {
+              sourceId: 'testSource',
+              getItems() {
+                return [];
+              },
+              templates: {
+                item({ item }) {
+                  return item.label;
+                },
+                noResults() {
+                  return 'No results template';
+                },
+              },
+            },
+          ];
+        },
+      });
+
+      // Focusing the input should render the panel
+      inputElement = container.querySelector('.aa-Input');
+      inputElement.focus();
+
+      // Focusing the input should open the panel
+      expect(onStateChange).toHaveBeenLastCalledWith(
+        expect.objectContaining({
+          state: expect.objectContaining({
+            isOpen: true,
+          }),
+        })
+      );
+
+      // Panel is rendered into the original container
+      await waitFor(() => {
+        expect(
+          panelContainer.querySelector<HTMLElement>('.aa-Panel')
+        ).toHaveTextContent('No results template');
+      });
+
+      // Update options (set `panelContainer` to a different element)
+      update({
+        panelContainer: panelContainer2,
+      });
+
+      // Focusing the input should render the panel
+      inputElement = container.querySelector('.aa-Input');
+      inputElement.focus();
+
+      // Panel is rendered into the new container
+      await waitFor(() => {
+        expect(
+          panelContainer2.querySelector<HTMLElement>('.aa-Panel')
+        ).toHaveTextContent('No results template');
+      });
+    });
+
     test('overrides the default id', async () => {
       const container = document.createElement('div');
 
diff --git a/packages/autocomplete-js/src/utils/__tests__/mergeDeep.test.ts b/packages/autocomplete-js/src/utils/__tests__/mergeDeep.test.ts
new file mode 100644
index 000000000..b47308b87
--- /dev/null
+++ b/packages/autocomplete-js/src/utils/__tests__/mergeDeep.test.ts
@@ -0,0 +1,46 @@
+import { mergeDeep } from '../mergeDeep';
+
+describe('mergeDeep', () => {
+  test('arrays', () => {
+    expect(mergeDeep({ key: ['test1'] }, { key: ['test2'] })).toEqual({
+      key: ['test1', 'test2'],
+    });
+  });
+
+  test('plain objects', () => {
+    expect(
+      mergeDeep({ key: { test1: 'value1' } }, { key: { test2: 'value2' } })
+    ).toEqual({
+      key: { test1: 'value1', test2: 'value2' },
+    });
+  });
+
+  test('HTML Elements', () => {
+    expect(
+      mergeDeep(
+        { key: document.createElement('div') },
+        { key: document.createElement('span') }
+      )
+    ).toEqual({
+      key: document.createElement('span'),
+    });
+  });
+
+  test('primitives', () => {
+    expect(mergeDeep({ key: 1 }, { key: 2 })).toEqual({
+      key: 2,
+    });
+  });
+
+  test('null', () => {
+    expect(mergeDeep({ key: 1 }, { key: null })).toEqual({
+      key: null,
+    });
+  });
+
+  test('undefined', () => {
+    expect(mergeDeep({ key: 1 }, { key: undefined })).toEqual({
+      key: undefined,
+    });
+  });
+});
diff --git a/packages/autocomplete-js/src/utils/mergeDeep.ts b/packages/autocomplete-js/src/utils/mergeDeep.ts
index ac464e88e..bfe148c6c 100644
--- a/packages/autocomplete-js/src/utils/mergeDeep.ts
+++ b/packages/autocomplete-js/src/utils/mergeDeep.ts
@@ -1,4 +1,7 @@
-const isObject = (value: unknown) => value && typeof value === 'object';
+const isPlainObject = (value: unknown) =>
+  value &&
+  typeof value === 'object' &&
+  Object.prototype.toString.call(value) === '[object Object]';
 
 export function mergeDeep(...values: any[]) {
   return values.reduce((acc, current) => {
@@ -8,7 +11,7 @@ export function mergeDeep(...values: any[]) {
 
       if (Array.isArray(accValue) && Array.isArray(currentValue)) {
         acc[key] = accValue.concat(...currentValue);
-      } else if (isObject(accValue) && isObject(currentValue)) {
+      } else if (isPlainObject(accValue) && isPlainObject(currentValue)) {
         acc[key] = mergeDeep(accValue, currentValue);
       } else {
         acc[key] = currentValue;