commit 4711099397061628d1cd4c6f3ab0e90fc8a85efa
Author: Joel Pittet <joel@pittet.ca>
Date:   Mon Mar 11 00:43:29 2013 -0700

    some more variable exists checks

diff --git a/core/modules/views/views_ui/templates/views-ui-build-group-filter-form.html.twig b/core/modules/views/views_ui/templates/views-ui-build-group-filter-form.html.twig
index 80d1f91..2c02e5a 100644
--- a/core/modules/views/views_ui/templates/views-ui-build-group-filter-form.html.twig
+++ b/core/modules/views/views_ui/templates/views-ui-build-group-filter-form.html.twig
@@ -35,15 +35,21 @@
   {{ required }}
 {% endif %}
 
-{{ operator }}
-{{ value }}
+{% if operator %}
+  {{ operator }}
+{% endif %}
+{% if value %}
+  {{ value }}
+{% endif %}
 
 <div class="views-left-40">
   {{ optional }}
   {{ remember }}
 </div>
 <div class="views-right-60">
-  {{ widget }}
+  {% if widget %}
+    {{ widget }}
+  {% endif %}
   {{ label }}
   {{ description }}
 </div>
diff --git a/core/modules/views/views_ui/templates/views-ui-expose-filter-form.html.twig b/core/modules/views/views_ui/templates/views-ui-expose-filter-form.html.twig
index 575172f..e420545 100644
--- a/core/modules/views/views_ui/templates/views-ui-expose-filter-form.html.twig
+++ b/core/modules/views/views_ui/templates/views-ui-expose-filter-form.html.twig
@@ -36,8 +36,12 @@
 {{ label }}
 {{ description }}
 
-{{ operator }}
-{{ value }}
+{% if operator %}
+  {{ operator }}
+{% endif %}
+{% if value %}
+  {{ value }}
+{% endif %}
 
 {% if use_operator %}
   <div class="views-left-40">
@@ -46,7 +50,9 @@
 {% endif %}
 
 <div class="views-right-60">
-  {{ widget }}
+  {% if widget %}
+    {{ widget }}
+  {% endif %}
   {{ label }}
   {{ description }}
 </div>
diff --git a/core/modules/views/views_ui/views_ui.theme.inc b/core/modules/views/views_ui/views_ui.theme.inc
index d74bc59..5b508aa 100644
--- a/core/modules/views/views_ui/views_ui.theme.inc
+++ b/core/modules/views/views_ui/views_ui.theme.inc
@@ -177,10 +177,15 @@ function template_preprocess_views_ui_build_group_filter_form(&$variables) {
     unset($form['required']);
   }
 
-  $variables['operator'] = $form['operator'];
-  $variables['value'] = $form['value'];
-  unset($form['operator']);
-  unset($form['value']);
+  if (isset($form['operator'])) {
+    $variables['operator'] = $form['operator'];
+    unset($form['operator']);
+  }
+
+  if (isset($form['value'])) {
+    $variables['value'] = $form['value'];
+    unset($form['value']);
+  }
 
   $variables['optional'] = $form['optional'];
   $variables['remember'] = $form['remember'];