Index: src/aphront/console/plugin/DarkConsoleXHProfPlugin.php
===================================================================
--- src/aphront/console/plugin/DarkConsoleXHProfPlugin.php
+++ src/aphront/console/plugin/DarkConsoleXHProfPlugin.php
@@ -87,7 +87,7 @@
           'target' => '_blank',
         ),
         pht('Profile Permalink'));
-      $result = phutil_tag(
+      $result[] = phutil_tag(
         'iframe',
         array('src' => "/xhprof/profile/$run/?frame=true"));
     } else {
Index: src/infrastructure/markup/PhabricatorMarkupEngine.php
===================================================================
--- src/infrastructure/markup/PhabricatorMarkupEngine.php
+++ src/infrastructure/markup/PhabricatorMarkupEngine.php
@@ -202,13 +202,16 @@
     PhabricatorMarkupInterface $object,
     $field) {
 
-    $custom = array_merge(
-      self::loadCustomInlineRules(),
-      self::loadCustomBlockRules());
-
-    $custom = mpull($custom, 'getRuleVersion', null);
-    ksort($custom);
-    $custom = PhabricatorHash::digestForIndex(serialize($custom));
+    static $custom;
+    if ($custom === null) {
+      $custom = array_merge(
+        self::loadCustomInlineRules(),
+        self::loadCustomBlockRules());
+
+      $custom = mpull($custom, 'getRuleVersion', null);
+      ksort($custom);
+      $custom = PhabricatorHash::digestForIndex(serialize($custom));
+    }
 
     return $object->getMarkupFieldKey($field).'@'.$this->version.'@'.$custom;
   }
@@ -364,6 +367,10 @@
       case 'default':
         $engine = self::newMarkupEngine(array());
         break;
+      case 'nolinebreaks':
+        $engine = self::newMarkupEngine(array());
+        $engine->setConfig('preserve-linebreaks', false);
+        break;
       case 'diviner':
         $engine = self::newMarkupEngine(array());
         $engine->setConfig('preserve-linebreaks', false);
Index: src/infrastructure/markup/PhabricatorMarkupOneOff.php
===================================================================
--- src/infrastructure/markup/PhabricatorMarkupOneOff.php
+++ src/infrastructure/markup/PhabricatorMarkupOneOff.php
@@ -36,10 +36,11 @@
   }
 
   public function newMarkupEngine($field) {
-    return PhabricatorMarkupEngine::newMarkupEngine(
-      array(
-        'preserve-linebreaks' => $this->preserveLinebreaks,
-      ));
+    if ($this->preserveLinebreaks) {
+      return PhabricatorMarkupEngine::getEngine();
+    } else {
+      return PhabricatorMarkupEngine::getEngine('nolinebreaks');
+    }
   }
 
   public function getMarkupText($field) {