diff --git a/core/admin/mailu/ui/templates/sidebar.html b/core/admin/mailu/ui/templates/sidebar.html
index 54448c8b..526b5908 100644
--- a/core/admin/mailu/ui/templates/sidebar.html
+++ b/core/admin/mailu/ui/templates/sidebar.html
@@ -96,9 +96,9 @@
       <li class="nav-header text-uppercase text-primary" role="none">{% trans %}Go to{% endtrans %}</li>
       {%- if config["WEBMAIL"] != "none" and current_user.is_authenticated %}
       <li class="nav-item" role="none">
-        <a href="{{ config["WEB_WEBMAIL"] }}" target="_blank" class="nav-link" role="menuitem">
+        <a href="{{ config["WEB_WEBMAIL"] }}" class="nav-link" role="menuitem">
         <i class="nav-icon far fa-envelope"></i>
-        <p>{% trans %}Webmail{% endtrans %} <i class="fas fa-external-link-alt text-xs"></i></p>
+        <p>{% trans %}Webmail{% endtrans %}</p>
         </a>
       </li>
       {%- endif %}
diff --git a/webmails/roundcube/config/config.inc.php b/webmails/roundcube/config/config.inc.php
index e8aedeff..160c7d26 100644
--- a/webmails/roundcube/config/config.inc.php
+++ b/webmails/roundcube/config/config.inc.php
@@ -59,6 +59,9 @@ $config['sso_logout_url'] = '/sso/logout';
 // configure enigma gpg plugin
 $config['enigma_pgp_homedir'] = '/data/gpg';
 
+// configure mailu button
+$config['show_mailu_button'] = {{ 'true' if ADMIN AND WEB_ADMIN else 'false' }};
+
 // set From header for DKIM signed message delivery reports
 $config['mdn_use_from'] = true;
 
diff --git a/webmails/roundcube/login/localization/en_US.inc b/webmails/roundcube/login/localization/en_US.inc
new file mode 100644
index 00000000..95e59383
--- /dev/null
+++ b/webmails/roundcube/login/localization/en_US.inc
@@ -0,0 +1,4 @@
+<?php
+$labels = [];
+$labels['mailu'] = 'Mailu';
+?>
diff --git a/webmails/roundcube/login/mailu.php b/webmails/roundcube/login/mailu.php
index 86de6562..4177c2ec 100644
--- a/webmails/roundcube/login/mailu.php
+++ b/webmails/roundcube/login/mailu.php
@@ -2,22 +2,41 @@
 
 class mailu extends rcube_plugin
 {
+  public $noajax = true;
 
   function init()
   {
+    // sso & mailu admin button
     $this->add_hook('startup', array($this, 'startup'));
+    // sso
     $this->add_hook('authenticate', array($this, 'authenticate'));
     $this->add_hook('login_after', array($this, 'login'));
     $this->add_hook('login_failed', array($this, 'login_failed'));
     $this->add_hook('logout_after', array($this, 'logout'));
+    // mailu admin button
+    $this->add_texts('localization/', false);
   }
 
   function startup($args)
   {
+    // mailu admin button
+    $rcmail = rcmail::get_instance();
+    if (!$rcmail->output->framed and $rcmail->config->get('show_mailu_button', false)) {
+      $this->include_stylesheet($this->local_skin_path() . '/mailu.css');
+      $this->add_button([
+          'type'       => 'link',
+          'href'       => $rcmail->config->get('support_url'),
+          'class'      => 'button-mailu',
+          'label'      => 'mailu.mailu',
+          'tabindex'   => '0',
+          'innerclass' => 'button-inner',
+        ], 'taskbar'
+      );
+    }
+    // sso
     if (empty($_SESSION['user_id'])) {
       $args['action'] = 'login';
     }
-
     return $args;
   }
 
diff --git a/webmails/roundcube/login/skins/classic/mailu.css b/webmails/roundcube/login/skins/classic/mailu.css
new file mode 100644
index 00000000..dd4068d0
--- /dev/null
+++ b/webmails/roundcube/login/skins/classic/mailu.css
@@ -0,0 +1,7 @@
+#taskbar a.button-mailu
+{
+  background-image: url('/static/mailu.png');
+  background-repeat: no-repeat;
+  background-size: 30px 30px;
+  background-position: -6px -4px;
+}
diff --git a/webmails/roundcube/login/skins/elastic/mailu.css b/webmails/roundcube/login/skins/elastic/mailu.css
new file mode 100644
index 00000000..a14d25b1
--- /dev/null
+++ b/webmails/roundcube/login/skins/elastic/mailu.css
@@ -0,0 +1,11 @@
+#taskmenu a.button-mailu {
+  background: url('/static/mailu.png');
+  background-repeat: no-repeat;
+  background-position: center;
+  background-position-y: 6px;
+  background-size: 22px 22px;
+}
+#taskmenu a.button-mailu.selected, #taskmenu a.button-mailu.selected:hover, #taskmenu a.button-mailu:hover {
+  color: #fff;
+  background-color: #45555c;
+}
diff --git a/webmails/roundcube/login/skins/larry/mailu.css b/webmails/roundcube/login/skins/larry/mailu.css
new file mode 100644
index 00000000..cc408d68
--- /dev/null
+++ b/webmails/roundcube/login/skins/larry/mailu.css
@@ -0,0 +1,10 @@
+#taskbar a.button-mailu span.button-inner {
+  background: url('/static/mailu.png');
+  background-repeat: no-repeat;
+  background-size: 22px 22px;
+  height: 19px;
+}
+#taskbar a.button-mailu.selected, #taskmenu a.button-mailu.selected:hover, #taskmenu a.button-mailu:hover {
+  color: #fff;
+  background-color: #45555c;
+}