diff --git a/web/app.js b/web/app.js
index 748c0514f..a4229a81d 100644
--- a/web/app.js
+++ b/web/app.js
@@ -2313,6 +2313,10 @@ function webViewerKeyDown(evt) {
       case 82: // 'r'
         PDFViewerApplication.rotatePages(90);
         break;
+
+      case 115: // F4
+        PDFViewerApplication.pdfSidebar.toggle();
+        break;
     }
 
     if (turnPage !== 0 &&