diff -u b/core/includes/ajax.inc b/core/includes/ajax.inc
--- b/core/includes/ajax.inc
+++ b/core/includes/ajax.inc
@@ -473,6 +473,11 @@
     // manipulation method is used. The method used is specified by
     // #ajax['method']. The default method is 'replaceWith', which completely
     // replaces the old wrapper element and its content with the new HTML.
+    // Since this is the primary response content returned to the client, we
+    // also attach the page title. It is up to client code to determine if and
+    // how to display that. For example, if the requesting element is configured
+    // to display the response in a dialog (via #ajax['dialog']), it can use
+    // this for the dialog title.
     $html = is_string($page_callback_result) ? $page_callback_result : drupal_render($page_callback_result);
     $commands[] = ajax_command_insert(NULL, $html) + array('title' => drupal_get_title());
     // Add the status messages inside the new content's wrapper element, so that
@@ -589,13 +594,22 @@
   if (isset($element['#ajax']['event'])) {
     $element['#attached']['library'][] = array('system', 'jquery.form');
     $element['#attached']['library'][] = array('system', 'drupal.ajax');
-    if (!empty($element['#ajax']['modal'])) {
+    if (!empty($element['#ajax']['dialog'])) {
       $element['#attached']['library'][] = array('system', 'drupal.dialog');
     }
 
     $settings = $element['#ajax'];
 
-    // Assign default settings.
+    // Assign default settings. When 'path' is set to NULL, ajax.js submits the
+    // Ajax request to the same URL as the form or link destination is for
+    // someone with JavaScript disabled. This is generally preferred as a way to
+    // ensure consistent server processing for js and no-js users, and Drupal's
+    // content negotiation takes care of formatting the response appropriately.
+    // However, 'path' and 'options' may be set when wanting server processing
+    // to be substantially different for a JavaScript triggered submission.
+    // One such substantial difference is form elements that use
+    // #ajax['callback'] for determining which part of the form needs
+    // re-rendering. For that, we have a special 'system/ajax' route.
     $settings += array(
       'path' => isset($settings['callback']) ? 'system/ajax' : NULL,
       'options' => array(),
diff -u b/core/misc/ajax.js b/core/misc/ajax.js
--- b/core/misc/ajax.js
+++ b/core/misc/ajax.js
@@ -78,37 +78,6 @@
 };
 
 /**
- * Makes sure that a hidden dom element with id 'drupal-modal' exists.
- */
-Drupal.behaviors.AJAXModalDialog = {
-  attach: function () {
-    if (!$('#drupal-modal').length) {
-      $('<div id="drupal-modal" />').hide().appendTo('body');
-    }
-  }
-};
-
-/**
- * Binds a listener on modal dialog creation to handle the cancel link.
- */
-$(window).on('dialog:aftercreate', function (e, dialog, $element, settings) {
-  if (settings.modal) {
-    $element.on('click.ajaxmodal', '.modal-cancel', function (e) {
-      dialog.close('cancel');
-      e.preventDefault();
-      e.stopPropagation();
-    });
-  }
-});
-
-/**
- * Removes all 'ajaxmodal' listeners.
- */
-$(window).on('dialog:beforeclose', function (e, dialog, $element) {
-  $element.off('.ajaxmodal');
-});
-
-/**
  * Ajax object.
  *
  * All Ajax objects on a page are accessible through the global Drupal.ajax
@@ -157,11 +126,13 @@
     this.wrapper = '#' + this.wrapper;
   }
 
-  // For Ajax responses that are wanted in a modal, use the needed wrapper and
-  // method.
-  if (this.modal) {
-    this.wrapper = '#drupal-modal';
+  // For Ajax responses that are wanted in a dialog, use the needed method.
+  // If wanted in a modal dialog, also use the needed wrapper.
+  if (this.dialog) {
     this.method = 'html';
+    if (this.dialog.modal) {
+      this.wrapper = '#drupal-modal';
+    }
   }
 
   this.element = element;
@@ -189,7 +160,7 @@
       //   figure out a work around to this problem, we prevent AJAX-enabling
       //   elements that submit to the same URL as the form when there's a file
       //   input. For example, this means the Delete button on the edit form of
-      //   an Article node doesn't open its confirmation form in a modal.
+      //   an Article node doesn't open its confirmation form in a dialog.
       if (this.form.find(':file').length) {
         return;
       }
@@ -587,8 +558,15 @@
     // Add the new content to the page.
     wrapper[method](new_content);
 
-    if (ajax.modal && (response.title || !$(ajax.wrapper).length)) {
-      Drupal.dialog(wrapper, {title: response.title}).showModal();
+    // If the requesting object wanted the response in a dialog, open that
+    // dialog. However, a single server response can include multiple insert
+    // commands (e.g., one for the primary content and another one for status
+    // messages), but we only want to open the dialog once, so we assume that
+    // only commands with a title property are dialog eligible.
+    // @todo Consider whether this is overloading title inappropriately, and
+    //   if so, find another way to determine dialog eligibility.
+    if (ajax.dialog && ('title' in response)) {
+      Drupal.dialog(wrapper, {title: response.title}).show(ajax.dialog);
     }
 
     // Immediately hide the new content if we're using any effects.
diff -u b/core/misc/dialog.js b/core/misc/dialog.js
--- b/core/misc/dialog.js
+++ b/core/misc/dialog.js
@@ -7,50 +7,76 @@
 (function ($, Drupal, drupalSettings) {
 
-  "use strict";
+"use strict";
 
-  drupalSettings.modal = {
-    autoOpen: true,
-    dialogClass: '',
-    close: function (e) {
-      Drupal.detachBehaviors(e.target, null, 'unload');
+drupalSettings.dialog = {
+  autoOpen: true,
+  dialogClass: '',
+  close: function (e) {
+    Drupal.detachBehaviors(e.target, null, 'unload');
+  }
+};
+
+Drupal.behaviors.dialog = {
+  attach: function () {
+    // Provide a known 'drupal-modal' dom element for Drupal code to use for
+    // modal dialogs. Since there can be multiple non-modal dialogs at a time,
+    // it is the responsibility of calling code to create the elements it needs.
+    if (!$('#drupal-modal').length) {
+      $('<div id="drupal-modal" />').hide().appendTo('body');
     }
-  };
+  }
+};
 
-  Drupal.dialog = function (element, options) {
+Drupal.dialog = function (element, options) {
 
-    function openDialog (settings) {
-      settings = $.extend(settings, defaults);
-      // Trigger a global event to allow scripts to bind events to the dialog.
-      $(window).trigger('dialog:beforecreate', [dialog, $element, settings]);
-      $element.dialog(settings);
-      dialog.open = true;
-      $(window).trigger('dialog:aftercreate', [dialog, $element, settings]);
-    }
+  function openDialog (settings) {
+    settings = $.extend(settings, defaults);
+    // Trigger a global event to allow scripts to bind events to the dialog.
+    $(window).trigger('dialog:beforecreate', [dialog, $element, settings]);
+    $element.dialog(settings);
+    dialog.open = true;
+    $(window).trigger('dialog:aftercreate', [dialog, $element, settings]);
+  }
+
+  function closeDialog (value) {
+    $(window).trigger('dialog:beforeclose', [dialog, $element]);
+    $element.dialog('close');
+    dialog.returnValue = value;
+    dialog.open = false;
+    $(window).trigger('dialog:afterclose', [dialog, $element]);
+  }
+
+  var undef;
+  var $element = $(element);
+  var defaults = $.extend(options, drupalSettings.dialog);
+  var dialog = {
+    open: false,
+    returnValue: undef,
+    show: function (settings) {
+      openDialog(settings);
+    },
+    close: closeDialog
+  };
 
-    function closeDialog (value) {
-      $(window).trigger('dialog:beforeclose', [dialog, $element]);
-      $element.dialog('close');
-      dialog.returnValue = value;
-      dialog.open = false;
-      $(window).trigger('dialog:afterclose', [dialog, $element]);
-    }
+  return dialog;
+};
 
-    var undef;
-    var $element = $(element);
-    var defaults = $.extend(options, drupalSettings.modal);
-    var dialog = {
-      open: false,
-      returnValue: undef,
-      show: function () {
-        openDialog({ modal: false });
-      },
-      showModal: function () {
-        openDialog({ modal: true });
-      },
-      close: closeDialog
-    };
+/**
+ * Binds a listener on dialog creation to handle the cancel link.
+ */
+$(window).on('dialog:aftercreate', function (e, dialog, $element, settings) {
+  $element.on('click.dialog', '.dialog-cancel', function (e) {
+    dialog.close('cancel');
+    e.preventDefault();
+    e.stopPropagation();
+  });
+});
 
-    return dialog;
-  };
+/**
+ * Removes all 'dialog' listeners.
+ */
+$(window).on('dialog:beforeclose', function (e, dialog, $element) {
+  $element.off('.dialog');
+});
 
 })(jQuery, Drupal, drupalSettings);
diff -u b/core/modules/node/lib/Drupal/node/NodeFormController.php b/core/modules/node/lib/Drupal/node/NodeFormController.php
--- b/core/modules/node/lib/Drupal/node/NodeFormController.php
+++ b/core/modules/node/lib/Drupal/node/NodeFormController.php
@@ -269,7 +269,7 @@
 
     // @todo Move this to EntityFormController::actions() so it applies to all
     //   entity types by default?
-    $element['delete']['#ajax']['modal'] = TRUE;
+    $element['delete']['#ajax']['dialog'] = array('modal' => TRUE);
 
     return $element;
   }
diff -u b/core/modules/node/node.admin.inc b/core/modules/node/node.admin.inc
--- b/core/modules/node/node.admin.inc
+++ b/core/modules/node/node.admin.inc
@@ -557,7 +557,7 @@
       $operations['delete'] = array(
         'title' => t('delete'),
         'href' => 'node/' . $node->nid . '/delete',
-        'ajax' => array('modal' => TRUE),
+        'ajax' => array('dialog' => array('modal' =>TRUE)),
         'query' => $destination,
       );
     }
diff -u b/core/modules/system/system.module b/core/modules/system/system.module
--- b/core/modules/system/system.module
+++ b/core/modules/system/system.module
@@ -1171,7 +1171,7 @@
     ),
   );
 
-  // Drupal's Ajax framework, modal component.
+  // Drupal's dialog component.
   $libraries['drupal.dialog'] = array(
     'title' => 'Drupal Dialog',
     'version' => VERSION,
@@ -3366,7 +3366,7 @@
     '#title' => $no ? $no : t('Cancel'),
     '#href' => $options['path'],
     '#attributes' => array(
-      'class' => array('modal-cancel'),
+      'class' => array('dialog-cancel'),
     ),
     '#options' => $options,
   );