2 files changed, 17 insertions, 2 deletions
diff --git a/misc/drupal.js b/misc/drupal.js
index ea688a499..87a5972c6 100644
--- a/misc/drupal.js
+++ b/misc/drupal.js
@@ -344,4 +344,15 @@ Drupal.theme.prototype = {
   }
 };
 
+/**
+ * Return whether the given variable is an object.
+ *
+ * The HEAD version of jQuery (http://code.jquery.com/jquery-nightly.js)
+ * includes an isObject() function, so when that gets released and incorporated
+ * into Drupal, this can be removed.
+ */
+$.extend({isObject: function(value) {
+  return (value !== null && typeof value === 'object');
+}});
+
 })(jQuery);
diff --git a/misc/tableheader.js b/misc/tableheader.js
index 813e4c7ca..0192d30b2 100644
--- a/misc/tableheader.js
+++ b/misc/tableheader.js
@@ -18,8 +18,9 @@ Drupal.behaviors.tableHeader = {
     var headers = [];
 
     $('table.sticky-enabled thead', context).once('tableheader', function () {
-      // Clone thead so it inherits original jQuery properties.
-      var headerClone = $(this).clone(true).insertBefore(this.parentNode).wrap('<table class="sticky-header"></table>').parent().css({
+      // Clone the table header so it inherits original jQuery properties. Hide
+      // the table to avoid a flash of the header clone upon page load.
+      var headerClone = $(this).clone(true).hide().insertBefore(this.parentNode).wrap('<table class="sticky-header"></table>').parent().css({
         position: 'fixed',
         top: '0px'
       });
@@ -32,6 +33,9 @@ Drupal.behaviors.tableHeader = {
       headerClone.table = table;
       // Finish initializing header positioning.
       tracker(headerClone);
+      // We hid the header to avoid it showing up erroneously on page load;
+      // we need to unhide it now so that it will show up when expected.
+      $(headerClone).children('thead').show();
 
       $(table).addClass('sticky-table');
     });