diff --git a/src/viewer.js b/src/viewer.js
index c66556f1..923bfd6b 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -2293,6 +2293,7 @@ function onCanvasKeyDown( event ) {
 function onCanvasKeyPress( event ) {
     if ( !event.preventDefaultAction && !event.ctrl && !event.alt && !event.meta ) {
         switch( event.keyCode ){
+            case 43://=|+
             case 61://=|+
                 this.viewport.zoomBy(1.1);
                 this.viewport.applyConstraints();