diff --git a/class/dashboard/subpage-main.php b/class/dashboard/subpage-main.php
index de48be7..d35b00f 100644
--- a/class/dashboard/subpage-main.php
+++ b/class/dashboard/subpage-main.php
@@ -38,7 +38,7 @@
  * @see <https://wordpress.org/support/topic/footnotes-is-not-amp-compatible/>
  * @since 2.3.1  footnote shortcode syntax validation  2021-01-01T0624+0100
  *
- * Last modified: 2021-01-01T0639+0100
+ * Last modified: 2021-01-01T1241+0100
  */
 
 /**
@@ -400,7 +400,7 @@ class MCI_Footnotes_Layout_Settings extends MCI_Footnotes_LayoutEngine {
                 // option to enable syntax validation:
                 "label-syntax" => $this->addLabel(MCI_Footnotes_Settings::C_BOOL_FOOTNOTE_SHORTCODE_SYNTAX_VALIDATION_ENABLE, __("Check for balanced shortcodes:", MCI_Footnotes_Config::C_STR_PLUGIN_NAME)),
                 "syntax" => $this->addSelectBox(MCI_Footnotes_Settings::C_BOOL_FOOTNOTE_SHORTCODE_SYNTAX_VALIDATION_ENABLE, $l_arr_Enable),
-                "notice-syntax" => __("In  the presence of an unclosed opening tag shortcode, a warning displays below the post title.", MCI_Footnotes_Config::C_STR_PLUGIN_NAME),
+                "notice-syntax" => __("In the presence of a lone start tag shortcode, a warning displays below the post title.", MCI_Footnotes_Config::C_STR_PLUGIN_NAME),
             )
         );
         // display template with replaced placeholders
diff --git a/class/task.php b/class/task.php
index 9fb9d2c..9808c30 100644
--- a/class/task.php
+++ b/class/task.php
@@ -66,7 +66,7 @@
  * @since 2.3.0  swap Custom CSS migration Boolean from 'migration complete' to 'show legacy'  2020-12-27T1243+0100
  * @since 2.3.1  syntax validation for balanced footnote start and end tags  2021-01-01T0227+0100
  *
- * Last modified:  2021-01-01T0642+0100
+ * Last modified:  2021-01-01T1239+0100
  */
 
 // If called directly, abort:
@@ -212,8 +212,7 @@ class MCI_Footnotes_Task {
      * @since 2.3.1
      * @var bool
      */
-    public static $l_bool_SyntaxErrorFlag = false;
-    public static $l_bool_SyntaxErrorShow = true;
+    public static $l_bool_SyntaxErrorFlag = true;
 
 
 
@@ -748,6 +747,8 @@ class MCI_Footnotes_Task {
      * @return string
      *
      * Edited since 2.0.0
+	 * 
+	 * @since 2.3.1  footnote shortcode syntax validation
      */
     public function search($p_str_Content, $p_bool_ConvertHtmlChars, $p_bool_HideFootnotesText) {
 
@@ -786,21 +787,21 @@ class MCI_Footnotes_Task {
             $l_str_ValidationRegex = '#' . $l_str_StartTagRegex . '(((?!' . $l_str_EndTagRegex . ').)*?)(' . $l_str_StartTagRegex . '|$)#s';
             preg_match( $l_str_ValidationRegex, $p_str_Content, $p_arr_ErrorLocation );
             if ( empty( $p_arr_ErrorLocation ) ) {
-                self::$l_bool_SyntaxErrorShow = false;
+                self::$l_bool_SyntaxErrorFlag = false;
             }
 
             // prevent generating and inserting the warning multiple times:
-            if ( self::$l_bool_SyntaxErrorShow ) {
+            if ( self::$l_bool_SyntaxErrorFlag ) {
                 $l_str_ErrorSpotString = strip_tags($p_arr_ErrorLocation[1]);
 
                 $l_str_SyntaxErrorWarning  = '<div class="footnotes_validation_error"><p>';
-                $l_str_SyntaxErrorWarning .= 'WARNING: unbalanced footnote start tag short code before:';
+                $l_str_SyntaxErrorWarning .= __("WARNING: unbalanced footnote start tag short code before:", MCI_Footnotes_Config::C_STR_PLUGIN_NAME);
                 $l_str_SyntaxErrorWarning .= '</p><p>“';
                 $l_str_SyntaxErrorWarning .= $l_str_ErrorSpotString;
                 $l_str_SyntaxErrorWarning .= '”</p></div>';
 
                 $p_str_Content = $l_str_SyntaxErrorWarning . $p_str_Content;
-                self::$l_bool_SyntaxErrorShow = false;
+                self::$l_bool_SyntaxErrorFlag = false;
 
                 return $p_str_Content;
             }
diff --git a/class/template.php b/class/template.php
index 6debbc8..ce5786b 100644
--- a/class/template.php
+++ b/class/template.php
@@ -9,11 +9,13 @@
  * Edited:
  * @since 2.0.3  further minify template content
  * @since 2.0.4  regex to delete multiple spaces
- * 
- * @since 2.3.0  support for custom templates in fixed location, while failing to add filter thanks to @misfist   2020-12-19T0606+0100
- * @see <https://wordpress.org/support/topic/template-override-filter/#post-13811141>
- * 
- * Last modified: 2020-12-20T0200+0100
+ *
+ * @since 2.2.6  support for custom templates in fixed location, while failing to add filter thanks to @misfist   2020-12-19T0606+0100
+ * @see <https://wordpress.org/support/topic/template-override-filter/>
+ * @since 2.3.1  templates may be in active theme, thanks to @misfist
+ * @see <https://wordpress.org/support/topic/template-override-filter/#post-13846598>
+ *
+ * Last modified: 2021-01-01T2214+0100
  */
 
 
@@ -74,11 +76,14 @@ class MCI_Footnotes_Template {
      * Edited:
      * @since 2.0.3  further minify template content
      * @since 2.0.4  regex to delete multiple spaces
+     *
+     * @since 2.2.6  support for custom templates   2020-12-19T0606+0100
+     * @see <https://wordpress.org/support/topic/template-override-filter/>
+     *
+     * @since 2.2.6  regex to delete a space before a closing pointy bracket
      * 
-     * @since 2.3.0  support for custom templates   2020-12-19T0606+0100
-     * @see <https://wordpress.org/support/topic/template-override-filter/#post-13811141>
-     * 
-     * @since 2.3.0  regex to delete space before >
+     * @since 2.3.1  look for custom template in the active theme
+     * @see <https://wordpress.stackexchange.com/questions/220942/how-to-get-the-active-themes-slug>
      */
     public function __construct($p_str_FileType, $p_str_FileName, $p_str_Extension = "html") {
         // no template file type and/or file name set
@@ -86,17 +91,28 @@ class MCI_Footnotes_Template {
             return;
         }
 
-        // First look for a custom template:
-
+        // First look for a custom template in a 'footnotes-custom' sibling folder:
         $l_str_TemplateFile = dirname(__FILE__) . "/../../footnotes-custom/templates/" . $p_str_FileType . "/" . $p_str_FileName . "." . $p_str_Extension;
+
+        // else load template from the active theme:
         if (!file_exists($l_str_TemplateFile)) {
 
+            $l_str_TemplateFile  = dirname(__FILE__) . "/../../../themes/";
+            // get active theme dir name (parent theme unlikely to contain custom templates):
+            // see <https://wordpress.stackexchange.com/questions/220942/how-to-get-the-active-themes-slug>
+            $l_str_TemplateFile .= get_stylesheet();
+            $l_str_TemplateFile .= "/templates/footnotes/" . $p_str_FileName . "." . $p_str_Extension;
+
             // else load internal template:
-            // get absolute path to the specified template file
-            $l_str_TemplateFile = dirname(__FILE__) . "/../templates/" . $p_str_FileType . "/" . $p_str_FileName . "." . $p_str_Extension;
-            // Template file does not exist
             if (!file_exists($l_str_TemplateFile)) {
-                return;
+
+                // get absolute path to the specified template file
+                $l_str_TemplateFile = dirname(__FILE__) . "/../templates/" . $p_str_FileType . "/" . $p_str_FileName . "." . $p_str_Extension;
+
+                // do nothing if template file does not exist:
+                if (!file_exists($l_str_TemplateFile)) {
+                    return;
+                }
             }
         }
 
diff --git a/footnotes.php b/footnotes.php
index 026b14e..9629b71 100755
--- a/footnotes.php
+++ b/footnotes.php
@@ -4,12 +4,12 @@
     Plugin URI: https://wordpress.org/plugins/footnotes/
     Description: time to bring footnotes to your website! footnotes are known from offline publishing and everybody takes them for granted when reading a magazine.
     Author: Mark Cheret
-    Version: 2.3.1d0
+    Version: 2.3.1d1
     Author URI: http://cheret.de/plugins/footnotes-2/
     Text Domain: footnotes
     Domain Path: /languages
 */
-define( 'FOOTNOTES_VERSION', '2.3.1d0' );
+define( 'FOOTNOTES_VERSION', '2.3.1d1' );
 /*
     Copyright 2020 Mark Cheret (email: mark@cheret.de)
 
diff --git a/readme.txt b/readme.txt
index 65180e6..95c1834 100755
--- a/readme.txt
+++ b/readme.txt
@@ -81,6 +81,7 @@ Visit this swift write-up from a **footnotes** user by the name of **Southwest**
 == Changelog ==
 
 = 2.3.1 =
+- Bugfix: Customization: support for custom templates in active theme, thanks to @misfist
 - Bugfix: Shortcodes: syntax validation for balanced footnote start and end tag short codes
 
 = 2.3.0 =
diff --git a/templates/note-for-developers.txt b/templates/note-for-developers.txt
index 74b7b93..dc54ea6 100644
--- a/templates/note-for-developers.txt
+++ b/templates/note-for-developers.txt
@@ -1,23 +1,41 @@
 note-for-developers.txt
 2020-12-19T0609+0100
-Last modified:  2020-12-19T0706+0100
+Last modified:  2021-01-01T2212+0100
 
-Footnotes plugin for WordPress, v2.3.0 and later
+Footnotes plugin for WordPress, v2.2.6 and later
 
 Support for custom templates
 ‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
 
-Since v2.3.0, Footnotes can process custom templates.
+Since v2.2.6, Footnotes supports custom templates.
 
-To use custom templates, please make a sibling of the "footnotes" folder called "footnotes-custom" containing just the content of templates/public/ with the same structure.
+Custom templates may be loaded from a sibling folder 'footnotes-custom'
+or since v2.3.1 from a folder 'templates/footnotes/' in the active theme.
 
-Existing homonymous templates on the path wp-content/plugins/footnotes-custom/templates/public/ are loaded instead of their counterparts in wp-content/plugins/footnotes/templates/public/.
+See footnotes/class/template.php:67..116
 
-The new location does not need to contain all templates.
-E.g. for custom tooltips, you need only one or both of these:
+
+A.  Active theme
+    ‾‾‾‾‾‾‾‾‾‾‾‾
+Please create a folder 'templates/footnotes/' in your child theme and
+store all your public custom templates for Footnotes directly therein.
+
+Existing homonymous templates are loaded instead of their counterparts in
+wp-content/plugins/footnotes/templates/public/.
+
+
+B.  Sibling folder
+    ‾‾‾‾‾‾‾‾‾‾‾‾‾‾
+Please make a sibling of the "footnotes" folder called 'footnotes-custom' and
+the same internal structure and file names as 'footnotes/templates/public/'.
+
+Example for custom tooltips:
 
 footnotes-custom
 └── templates
     └── public
         ├── footnote.html
         └── tooltip.html
+
+The timing parameters in the inline jQuery script 'tooltip.html' are already
+configurable in the dashboard > Referrers and tooltips > Tooltip timing.