diff --git a/core/misc/splitbutton/splitbutton.es6.js b/core/misc/splitbutton/splitbutton.es6.js
index b1bdaa3357..88fe3f5982 100644
--- a/core/misc/splitbutton/splitbutton.es6.js
+++ b/core/misc/splitbutton/splitbutton.es6.js
@@ -70,7 +70,8 @@
       // If this.menuItems is empty, the initialization hasn't occurred yet.
       if (this.menuItems.length === 0) {
         const itemTags =
-          this.menu.getAttribute('data-drupal-splitbutton-item-tags') || 'a, input, button';
+          this.menu.getAttribute('data-drupal-splitbutton-item-tags') ||
+          'a, input, button';
         Array.prototype.slice
           .call(this.menu.querySelectorAll(itemTags))
           .forEach((item, index) => {
@@ -132,7 +133,7 @@
       )
         ? 'close'
         : 'open';
-      this[state]();
+      this[state](e.detail === 0);
     }
 
     /**
@@ -158,7 +159,7 @@
     /**
      * Opens splitbutton menu.
      */
-    open() {
+    open(focusFirst = true) {
       this.initMenuItems();
       this.toggle(true);
       if (!this.hasOwnProperty('popper')) {
@@ -166,9 +167,12 @@
       } else {
         this.popper.forceUpdate();
       }
-      // Wrap in a zero-wait timeout to ensure it isn't called until
-      // initMenuItems() completes.
-      setTimeout(() => this.focusFirst(), 0);
+
+      if (focusFirst) {
+        // Wrap in a zero-wait timeout to ensure it isn't called until
+        // initMenuItems() completes.
+        setTimeout(() => this.focusFirst(), 0);
+      }
     }
 
     /**
diff --git a/core/misc/splitbutton/splitbutton.js b/core/misc/splitbutton/splitbutton.js
index e8b37a30a3..645be5dac1 100644
--- a/core/misc/splitbutton/splitbutton.js
+++ b/core/misc/splitbutton/splitbutton.js
@@ -106,7 +106,7 @@ function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _d
         e.preventDefault();
         e.stopPropagation();
         var state = this.splitbutton.hasAttribute('data-drupal-splitbutton-open') ? 'close' : 'open';
-        this[state]();
+        this[state](e.detail === 0);
       }
     }, {
       key: "toggle",
@@ -128,6 +128,7 @@ function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _d
       value: function open() {
         var _this3 = this;
 
+        var focusFirst = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : true;
         this.initMenuItems();
         this.toggle(true);
 
@@ -137,9 +138,11 @@ function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _d
           this.popper.forceUpdate();
         }
 
-        setTimeout(function () {
-          return _this3.focusFirst();
-        }, 0);
+        if (focusFirst) {
+          setTimeout(function () {
+            return _this3.focusFirst();
+          }, 0);
+        }
       }
     }, {
       key: "close",