diff --git a/acp/main_module.php b/acp/main_module.php
index 9f23939..3f98df6 100644
--- a/acp/main_module.php
+++ b/acp/main_module.php
@@ -40,20 +40,23 @@ public function main($id, $mode)
 
             $theme = $request->variable('oxcom_phpbbch_theme', 'none');
             $langs = $request->variable('oxcom_phpbbch_langs', ['none']);
+            $bFExt = $request->variable('oxcom_phpbbch_bh_format_ext', 'N');
 
             $this->config->set('oxcom_phpbbch_theme', $theme);
+            $this->config->set('oxcom_phpbbch_format_only', $bFExt);
             $this->updateLanguages($langs);
 
             trigger_error($this->lang('ACP_PHPBBCH_SETTING_SAVED') . adm_back_link($this->u_action));
         }
 
         $template->assign_vars([
-            'ACP_PHPBBCH_LANGUAGES' => \oxcom\phpbbch\core\settings::getLanguages(),
-            'ACP_PHPBBCH_THEMES'    => \oxcom\phpbbch\core\settings::getThemes(),
-            'ACP_PHPBBCH_THEME'     => $this->config['oxcom_phpbbch_theme'],
-            'ACP_PHPBBCH_LANGS'     => $this->getSelectedLanguages(),
-            'ACP_PHPBBCH_VERSION'   => $this->config['oxcom_phpbbch_version'],
-            'U_ACTION'              => $this->u_action,
+            'ACP_PHPBBCH_LANGUAGES'          => \oxcom\phpbbch\core\settings::getLanguages(),
+            'ACP_PHPBBCH_THEMES'             => \oxcom\phpbbch\core\settings::getThemes(),
+            'ACP_PHPBBCH_THEME'              => $this->config['oxcom_phpbbch_theme'],
+            'ACP_PHPBBCH_LANGS'              => $this->getSelectedLanguages(),
+            'ACP_PHPBBCH_VERSION'            => $this->config['oxcom_phpbbch_version'],
+            'ACP_PHPBBCH_BEHAVIOUR_EXT_ONLY' => $this->config['oxcom_phpbbch_format_only'],
+            'U_ACTION'                       => $this->u_action,
         ]);
     }
 
diff --git a/adm/style/acp_phpbbch_body.html b/adm/style/acp_phpbbch_body.html
index d76af0e..06db4c4 100644
--- a/adm/style/acp_phpbbch_body.html
+++ b/adm/style/acp_phpbbch_body.html
@@ -7,10 +7,7 @@ <h1>{L_SETTINGS}</h1>
         <dl>
             <dt>
                 <label for="oxcom_phpbbch_theme">{L_ACP_PHPBBCH_THEME}</label>
-                <p>
-                    Please visit this site to get more information about themes
-                    <a href="https://highlightjs.org/" target="_blank" title="HighlightJS">HighlightJS</a>
-                </p>
+                <p>{L_ACP_PHPBBCH_THEME_D} <a href="https://highlightjs.org/" target="_blank" title="HighlightJS">HighlightJS</a></p>
             </dt>
             <dd>
                 <select class="select" id="oxcom_phpbbch_theme" name="oxcom_phpbbch_theme">
@@ -23,6 +20,20 @@ <h1>{L_SETTINGS}</h1>
             </dd>
         </dl>
 
+        <dl>
+            <dt>
+                <label>{L_ACP_PHPBBCH_BEHAVIOUR}</label>
+                <p>{L_ACP_PHPBBCH_BEHAVIOUR_D}</p>
+            </dt>
+            <dd>
+                <input type="checkbox" class="checkbox"
+                       id="oxcom_phpbbch_bh_format_ext"
+                       name="oxcom_phpbbch_bh_format_ext"
+                       value="Y"
+                       {% if ACP_PHPBBCH_BEHAVIOUR_EXT_ONLY == 'Y' %}checked="checked"{% endif %}
+                />&nbsp;<label for="oxcom_phpbbch_bh_format_ext">{L_ACP_PHPBBCH_BEHAVIOUR_EXT_ONLY}</label>
+            </dd>
+        </dl>
         <dl>
             <dt>
                 <label>{L_ACP_PHPBBCH_LANGUAGES}</label>
@@ -36,10 +47,11 @@ <h1>{L_SETTINGS}</h1>
             <dd>
             {% for key,title in ACP_PHPBBCH_LANGUAGES %}
                 <input type="checkbox" class="checkbox"
+                       id="oxcom_phpbbch_langs_i_{{ key }}"
                        name="oxcom_phpbbch_langs[]"
                        value="{{ key }}"
                        {% if key in ACP_PHPBBCH_LANGS %} checked="checked" {% endif %}
-                />&nbsp;{{ title }}
+                />&nbsp;<label for="oxcom_phpbbch_langs_i_{{ key }}">{{ title }}</label>
                 <br />
             {% endfor %}
             </dd>
diff --git a/event/main.php b/event/main.php
index ae6e518..5c94075 100644
--- a/event/main.php
+++ b/event/main.php
@@ -78,7 +78,7 @@ public function initExtension($event)
         $enabled   = $this->getSelectedLanguages();
 
         foreach ($available as $key => $name) {
-            if (in_array($key, $enabled, true)) {
+            if (\in_array($key, $enabled, true)) {
                 continue;
             }
 
@@ -86,8 +86,9 @@ public function initExtension($event)
         }
 
         $this->template->assign_vars([
-            'PHPBBCH_ALLOWED_LANGS'   => array_keys($available),
-            'PHPBBCH_POST_HELP_LANGS' => $available,
+            'PHPBBCH_ALLOWED_LANGS'      => \array_keys($available),
+            'PHPBBCH_POST_HELP_LANGS'    => $available,
+            'PHPBBCH_BEHAVIOUR_EXT_ONLY' => $this->config['oxcom_phpbbch_format_only'],
         ]);
     }
 
@@ -99,20 +100,16 @@ public function initExtension($event)
      */
     protected function getSelectedLanguages()
     {
-        $config = $this->config;
-
         $allowed = \oxcom\phpbbch\core\settings::getLanguages();
         $allowed = array_keys($allowed);
 
         // get list of selected languages
-        $enabled = array_filter($allowed, function ($key) use ($config) {
-            $key    = 'oxcom_phpbbch_lang_' . $key;
+        return \array_filter($allowed, function ($key) {
+            $key    = 'oxcom_phpbbch_lang_'.$key;
             $status = $this->config[$key];
 
             return !empty($status) && $status === main_module::ENUM_ALLOWED_YES;
         });
-
-        return $enabled;
     }
 
     /**
diff --git a/language/en/phpbbch.php b/language/en/phpbbch.php
index 8f58b23..ca9fc8c 100644
--- a/language/en/phpbbch.php
+++ b/language/en/phpbbch.php
@@ -19,6 +19,11 @@
 
     'ACP_PHPBBCH_LANGUAGES' => 'Languages',
     'ACP_PHPBBCH_THEME'     => 'Theme',
+    'ACP_PHPBBCH_THEME_D'     => 'Please visit this site to get more information about themes',
+    'ACP_PHPBBCH_BEHAVIOUR' => 'Behaviour',
+    'ACP_PHPBBCH_BEHAVIOUR_D' => 'Customize plugin behaviour.',
+
+    'ACP_PHPBBCH_BEHAVIOUR_EXT_ONLY' => 'Force formatting only code blocks created by this extension only.',
 
     'PHPBBCH_POST_TAB_TITLE' => 'Syntax Highlight',
     'PHPBBCH_POST_TAB_HELP'  => 'Please find list of available languages',
diff --git a/migrations/format_only_ext.php b/migrations/format_only_ext.php
new file mode 100644
index 0000000..f794841
--- /dev/null
+++ b/migrations/format_only_ext.php
@@ -0,0 +1,41 @@
+<?php
+
+namespace oxcom\phpbbch\migrations;
+
+class format_only_ext extends \phpbb\db\migration\migration
+{
+    /**
+     * If our config variable already exists in the db
+     * skip this migration.
+     */
+    public function effectively_installed()
+    {
+        return isset($this->config['oxcom_phpbbch_format_only']);
+    }
+
+    /**
+     * This migration depends on phpBB's v314 migration
+     * already being installed.
+     */
+    static public function depends_on()
+    {
+        return [
+            '\phpbb\db\migration\data\v31x\v314',
+            '\oxcom\phpbbch\migrations\add_module',
+        ];
+    }
+
+    public function update_data()
+    {
+        return [
+            ['config.add', ['oxcom_phpbbch_format_only', 'N']],
+        ];
+    }
+
+    public function revert_data()
+    {
+        return [
+            ['config.remove', ['oxcom_phpbbch_format_only']],
+        ];
+    }
+}
diff --git a/styles/all/template/js/init.js b/styles/all/template/js/init.js
index 5c32f20..d4a6798 100644
--- a/styles/all/template/js/init.js
+++ b/styles/all/template/js/init.js
@@ -4,7 +4,9 @@ $(function () {
         tabReplace: '    ' // 4 spaces
     });
 
-    $('code')
+    var selector =  window.oxcom_phpbbch_config.behavior.format_only_ext ? "code[data-bind=\'phpbbch-code\']" : 'code';
+
+    $(selector)
         .each(function (i, block) {
             if ($(block).data('bind') !== 'phpbbch-code') {
                 var content = $(block).html();
diff --git a/styles/all/template/phpbbch_init.html b/styles/all/template/phpbbch_init.html
index 75847bf..f20c534 100644
--- a/styles/all/template/phpbbch_init.html
+++ b/styles/all/template/phpbbch_init.html
@@ -1,3 +1,11 @@
+<script type="text/javascript">
+    window.oxcom_phpbbch_config = {
+        behavior: {
+            format_only_ext: {{ PHPBBCH_BEHAVIOUR_EXT_ONLY == 'Y' ? 'true' : 'false' }}
+    }
+    };
+</script>
+
 {% INCLUDEJS '@oxcom_phpbbch/js/higlightjs/highlight.min.js' %}
 
 {% for lang in PHPBBCH_ALLOWED_LANGS %}