diff --git a/web/app.js b/web/app.js
index c4b04559d..5af753a99 100644
--- a/web/app.js
+++ b/web/app.js
@@ -2968,17 +2968,13 @@ function webViewerKeyDown(evt) {
       case 107: // FF '+' and '='
       case 187: // Chrome '+'
       case 171: // FF with German keyboard
-        if (!isViewerInPresentationMode) {
-          PDFViewerApplication.zoomIn();
-        }
+        PDFViewerApplication.zoomIn();
         handled = true;
         break;
       case 173: // FF/Mac '-'
       case 109: // FF '-'
       case 189: // Chrome '-'
-        if (!isViewerInPresentationMode) {
-          PDFViewerApplication.zoomOut();
-        }
+        PDFViewerApplication.zoomOut();
         handled = true;
         break;
       case 48: // '0'