diff --git a/ChangeLog b/ChangeLog
index 79cbd46b..2b9dd462 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2015-12-30  Uwe Tews
+
+    * fixed plugin filepath cache must not be static, because of possible problem
+      when using multiple Smarty instances with diffrent plugins_dir settings
+         https://github.com/smarty-php/smarty/issues/146 
+
 2015-06-21  Uwe Tews
 
     * PHP7 raises E_DEPRECATED use __construct for compatibility 
diff --git a/libs/Smarty.class.php b/libs/Smarty.class.php
index 1aae5e66..411ddfa1 100644
--- a/libs/Smarty.class.php
+++ b/libs/Smarty.class.php
@@ -562,6 +562,12 @@ class Smarty
      */
     var $_cache_including = false;
 
+    /**
+     * plugin filepath cache
+     *
+     * @var array
+     */
+    var $_filepaths_cache = array();
     /**#@-*/
     /**
      * The class constructor.
diff --git a/libs/internals/core.assemble_plugin_filepath.php b/libs/internals/core.assemble_plugin_filepath.php
index 690d3ddb..22c02483 100644
--- a/libs/internals/core.assemble_plugin_filepath.php
+++ b/libs/internals/core.assemble_plugin_filepath.php
@@ -14,11 +14,9 @@
  */
 function smarty_core_assemble_plugin_filepath($params, &$smarty)
 {
-    static $_filepaths_cache = array();
-
     $_plugin_filename = $params['type'] . '.' . $params['name'] . '.php';
-    if (isset($_filepaths_cache[$_plugin_filename])) {
-        return $_filepaths_cache[$_plugin_filename];
+    if (isset($smarty->_filepaths_cache[$_plugin_filename])) {
+        return $smarty->_filepaths_cache[$_plugin_filename];
     }
     $_return = false;
 
@@ -58,7 +56,7 @@ function smarty_core_assemble_plugin_filepath($params, &$smarty)
             }
         }
     }
-    $_filepaths_cache[$_plugin_filename] = $_return;
+    $smarty->_filepaths_cache[$_plugin_filename] = $_return;
     return $_return;
 }