don't use $(document).append (it's wrong and broken)

IPython/frontend/html/notebook/static/notebook/js/notebook.js

@@ -1343,7 +1343,7 b' var IPython = (function (IPython) {'
         var that = this;
         var dialog = $('<div/>');
         dialog.html('Do you want to restart the current kernel?  You will lose all variables defined in it.');
-        $(document).append(dialog);
+        $(document.body).append(dialog);
         dialog.dialog({
             resizable: false,
             modal: true,
@@ -1934,7 +1934,7 b' var IPython = (function (IPython) {'
             ).css("text-align", "center")
         );
         
-        $(document).append(dialog);
+        $(document.body).append(dialog);
         
         dialog.dialog({
             resizable: false,

IPython/frontend/html/notebook/static/notebook/js/notificationarea.js

@@ -99,7 +99,7 b' var IPython = (function (IPython) {'
                 ' the notebook, but running code will no longer work until the notebook' +
                 ' is reopened.'
             );
-            $(document).append(dialog);
+            $(document.body).append(dialog);
             dialog.dialog({
                 resizable: false,
                 modal: true,
@@ -136,7 +136,7 b' var IPython = (function (IPython) {'
                 " network connection or notebook server configuration.";
             var dialog = $('<div/>');
             dialog.html(msg);
-            $(document).append(dialog);
+            $(document.body).append(dialog);
             dialog.dialog({
                 resizable: false,
                 modal: true,

IPython/frontend/html/notebook/static/notebook/js/savewidget.js

@@ -79,7 +79,7 b' var IPython = (function (IPython) {'
             .addClass('ui-widget ui-widget-content')
             .attr('value',IPython.notebook.get_notebook_name())
         );
-        // $(document).append(dialog);
+        // $(document.body).append(dialog);
         dialog.dialog({
             resizable: false,
             modal: true,