diff -u b/core/misc/collapse.es6.js b/core/misc/collapse.es6.js
--- b/core/misc/collapse.es6.js
+++ b/core/misc/collapse.es6.js
@@ -156,13 +156,18 @@
     if ($item.length) {
       // Open all (nested) parent details and set aria attributes on the summary
       // by triggering the click event listener in details-aria.js.
-      $item.parents('details').not('[open]').find('> summary').trigger('click.detailsAria');
+      $item.parents('details').not('[open]').find('> summary').trigger('click');
 
       // Loop over all (nested) parent vertical tabs and focus them in order
       // to reveal the children.
       $item.parents('.vertical-tabs__pane').each((index, pane) => {
         $(pane).data('verticalTab').focus();
       });
+
+      // Clicking the anchor should set focus, but timing issues in Edge need this.
+      setTimeout(function() {
+        $item.focus();
+      }, 300, $item);
     }
   };
 
diff -u b/core/misc/collapse.js b/core/misc/collapse.js
--- b/core/misc/collapse.js
+++ b/core/misc/collapse.js
@@ -86,11 +86,15 @@
     var $item = e.type === 'click' ? $(e.currentTarget.hash) : $('#' + location.hash.substr(1));
 
     if ($item.length) {
-      $item.parents('details').not('[open]').find('> summary').trigger('click.detailsAria');
+      $item.parents('details').not('[open]').find('> summary').trigger('click');
 
       $item.parents('.vertical-tabs__pane').each(function (index, pane) {
         $(pane).data('verticalTab').focus();
       });
+
+      setTimeout(function () {
+        $item.focus();
+      }, 300, $item);
     }
   };