diff --git a/modules/system/classes/PluginManager.php b/modules/system/classes/PluginManager.php
index 1d6c0aa10..1322697d4 100644
--- a/modules/system/classes/PluginManager.php
+++ b/modules/system/classes/PluginManager.php
@@ -208,21 +208,17 @@ class PluginManager
      */
     public function registerPlugin($plugin, $pluginId = null)
     {
-        if (!$pluginId) {
-            $pluginId = $this->getIdentifier($plugin);
-        }
-
-        if (!$plugin) {
-            return;
-        }
-
         /**
          * Verify that the provided plugin should be registered
          */
-        if ($plugin->disabled || (self::$noInit && !$plugin->elevated)) {
+        if (!$plugin || $plugin->disabled || (self::$noInit && !$plugin->elevated)) {
             return;
         }
 
+        if (!$pluginId) {
+            $pluginId = $this->getIdentifier($plugin);
+        }
+
         $pluginPath = $this->getPluginPath($plugin);
         $pluginNamespace = strtolower($pluginId);
 
@@ -609,7 +605,7 @@ class PluginManager
     {
         $code = $this->getIdentifier($id);
         $code = $this->normalizeIdentifier($code);
-        if (array_key_exists($code, $this->disabledPlugins)) {
+        if (isset($this->disabledPlugins[$code])) {
             return false;
         }
 
@@ -634,7 +630,7 @@ class PluginManager
     {
         $code = $this->getIdentifier($id);
         $code = $this->normalizeIdentifier($code);
-        if (!array_key_exists($code, $this->disabledPlugins)) {
+        if (!isset($this->disabledPlugins[$code])) {
             return false;
         }