diff --git a/ts/quill/mentions/completion.tsx b/ts/quill/mentions/completion.tsx
index 7335745b27c6..7e6652f1886b 100644
--- a/ts/quill/mentions/completion.tsx
+++ b/ts/quill/mentions/completion.tsx
@@ -1,4 +1,4 @@
-// Copyright 2020-2021 Signal Messenger, LLC
+// Copyright 2020-2022 Signal Messenger, LLC
 // SPDX-License-Identifier: AGPL-3.0-only
 
 import _ from 'lodash';
@@ -27,15 +27,6 @@ export type MentionCompletionOptions = {
   theme: ThemeType;
 };
 
-declare global {
-  // We want to extend `HTMLElement`'s properties, so we need an interface.
-  // eslint-disable-next-line no-restricted-syntax
-  interface HTMLElement {
-    // Webkit-specific
-    scrollIntoViewIfNeeded: (bringToCenter: boolean) => void;
-  }
-}
-
 const MENTION_REGEX = /(?:^|\W)@([-+\w]*)$/;
 
 export class MentionCompletion {
diff --git a/ts/window.d.ts b/ts/window.d.ts
index 80cd1773eb58..481f86857b18 100644
--- a/ts/window.d.ts
+++ b/ts/window.d.ts
@@ -498,6 +498,13 @@ declare global {
     stackForLog?: string;
   }
 
+  // We want to extend `Element`'s properties, so we need an interface.
+  // eslint-disable-next-line no-restricted-syntax
+  interface Element {
+    // WebKit-specific
+    scrollIntoViewIfNeeded: (bringToCenter?: boolean) => void;
+  }
+
   // Uint8Array and ArrayBuffer are type-compatible in TypeScript's covariant
   // type checker, but in reality they are not. Let's assert correct use!
   interface Uint8Array {