diff --git a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.js b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
similarity index 95%
rename from polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.js
rename to polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
index b5393ea..40f6a32 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-mode-selector/gr-diff-mode-selector_html.ts
@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import {html} from '@polymer/polymer/lib/utils/html-tag.js';
+import {html} from '@polymer/polymer/lib/utils/html-tag';
 
 export const htmlTemplate = html`
   <style include="shared-styles">