diff --git a/config/global.ini.php b/config/global.ini.php
index 1114efc681f..a818c3248c9 100644
--- a/config/global.ini.php
+++ b/config/global.ini.php
@@ -236,7 +236,7 @@
 ; maximum number of rows for any of the Actions tables (pages, downloads, outlinks)
 datatable_archiving_maximum_rows_actions = 500
 ; maximum number of rows for pages in categories (sub pages, when clicking on the + for a page category)
-; note: should not exceed the display limit in Piwik_Actions_Controller::ACTIONS_REPORT_ROWS_DISPLAY
+; note: should not exceed the display limit in Piwik\Actions\Controller::ACTIONS_REPORT_ROWS_DISPLAY
 ; because each subdirectory doesn't have paging at the bottom, so all data should be displayed if possible.
 datatable_archiving_maximum_rows_subtable_actions = 100
 
diff --git a/core/AssetManager.php b/core/AssetManager.php
index 79f81fafe1c..086f538a3f5 100644
--- a/core/AssetManager.php
+++ b/core/AssetManager.php
@@ -254,7 +254,18 @@ private static function getCssFiles()
     {
         $cssFiles = array();
         Piwik_PostEvent(self::CSS_IMPORT_EVENT, array(&$cssFiles));
+
         $cssFiles = self::sortCssFiles($cssFiles);
+
+        // We also look for the currently enabled theme and add CSS from the json
+        $theme = PluginsManager::getInstance()->getThemeEnabled();
+        if($theme) {
+            $info = $theme->getInformation();
+            if(isset($info['stylesheet'])) {
+                $themeStylesheetFile = 'plugins/'. $theme->getPluginName() . '/' . $info['stylesheet'];
+            }
+            $cssFiles[] = $themeStylesheetFile;
+        }
         return $cssFiles;
     }
 
diff --git a/core/PluginsManager.php b/core/PluginsManager.php
index 50ede0d98df..faea3d3b234 100644
--- a/core/PluginsManager.php
+++ b/core/PluginsManager.php
@@ -283,8 +283,9 @@ public function activatePlugin($pluginName)
         }
 
         // Only one theme enabled at a time
-        $themeAlreadyEnabled = $this->getThemeEnabled();
-        if($themeAlreadyEnabled) {
+        $themeEnabled = $this->getThemeEnabled();
+        if($themeEnabled) {
+            $themeAlreadyEnabled = $themeEnabled->getPluginName();
             $plugin = $this->loadPlugin($pluginName);
             if($plugin->isTheme()) {
                 $plugins = $this->deactivatePlugin( $themeAlreadyEnabled, $plugins );
@@ -325,16 +326,16 @@ protected function isPluginInFilesystem($pluginName)
      * Returns the name of the non default theme currently enabled.
      * If Zeitgeist is enabled, returns false (nb: Zeitgeist cannot be disabled)
      *
-     * @return string
+     * @return Plugin
      */
-    protected function getThemeEnabled()
+    public function getThemeEnabled()
     {
         $plugins = $this->getLoadedPlugins();
         foreach($plugins as $plugin) {
             /* @var $plugin Plugin */
             if($plugin->isTheme()
                 && $plugin->getPluginName() != self::DEFAULT_THEME) {
-                return $plugin->getPluginName();
+                return $plugin;
             }
         }
         return false;
diff --git a/core/ViewDataTable.php b/core/ViewDataTable.php
index 3744eb71601..a75b2354d59 100644
--- a/core/ViewDataTable.php
+++ b/core/ViewDataTable.php
@@ -977,8 +977,7 @@ public function hasReportBeenPurged()
             $reportYear = $reportDate->toString('Y');
             $reportMonth = $reportDate->toString('m');
 
-            //TODOA
-            if (class_exists('Piwik\Plugins\PrivacyManager\PrivacyManager')
+            if (PluginsManager::getInstance()->isPluginActivated('PrivacyManager')
                 && Plugins\PrivacyManager\PrivacyManager::shouldReportBePurged($reportYear, $reportMonth)
             ) {
                 return true;
@@ -1013,7 +1012,6 @@ private function getBaseReportUrl($module, $action, $queryParams = array())
      */
     static public function renderReport($pluginName, $apiAction, $fetch = true)
     {
-        //TODOA
         $namespacedApiClassName = "\\Piwik\\Plugins\\$pluginName\\API";
         if (!method_exists($namespacedApiClassName::getInstance(), $apiAction)) {
             throw new \Exception("$namespacedApiClassName Invalid action name '$apiAction' for '$pluginName' plugin.");
diff --git a/plugins/Goals/Archiver.php b/plugins/Goals/Archiver.php
index ae0cbf3b079..efb26854bc4 100644
--- a/plugins/Goals/Archiver.php
+++ b/plugins/Goals/Archiver.php
@@ -16,6 +16,7 @@
 use Piwik\DataTable;
 use Piwik\DataArray;
 use Piwik\PluginsArchiver;
+use Piwik\PluginsManager;
 use Piwik\Tracker\GoalManager;
 use Piwik\Plugins\Goals\Goals;
 
@@ -333,8 +334,7 @@ protected function cleanupRowGetLabel(&$row, $currentField)
             }
             $label = "Value not defined";
             // Product Name/Category not defined"
-            //TODOA : working?
-            if (class_exists('Piwik\Plugins\CustomVariables\CustomVariables')) {
+            if (PluginsManager::getInstance()->isPluginActivated('CustomVariables')) {
                 $label = \Piwik\Plugins\CustomVariables\Archiver::LABEL_CUSTOM_VALUE_NOT_DEFINED;
             }
         }
diff --git a/plugins/PleineLune/PleineLune.php b/plugins/PleineLune/PleineLune.php
deleted file mode 100644
index c1189727ba7..00000000000
--- a/plugins/PleineLune/PleineLune.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-/**
- * Piwik - Open source web analytics
- *
- * @link http://piwik.org
- * @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
- *
- * @category Piwik_Plugins
- * @package PleineLune
- */
-namespace Piwik\Plugins\PleineLune;
-
-use Piwik\AssetManager;
-
-/**
- *
- * @package PleineLune
- */
-class PleineLune extends \Piwik\Plugin
-{
-    public function getListHooksRegistered()
-    {
-        return array(
-            AssetManager::CSS_IMPORT_EVENT => 'getCssFiles',
-        );
-    }
-
-    public function getCssFiles(&$cssFiles)
-    {
-        $cssFiles[] = "plugins/PleineLune/stylesheets/theme.less";
-    }
-}
diff --git a/plugins/PleineLune/plugin.piwik.json b/plugins/PleineLune/plugin.piwik.json
index d0718e1737d..b3ab4ac732b 100644
--- a/plugins/PleineLune/plugin.piwik.json
+++ b/plugins/PleineLune/plugin.piwik.json
@@ -1,5 +1,6 @@
 {
     "name": "PleineLune",
     "description": "A dark theme for Piwik, ideal to view your analytics reports before sunrise.",
-    "theme": true
+    "theme": true,
+    "stylesheet": "stylesheets/theme.less"
 }
\ No newline at end of file