diff --git a/admin/themes/default/js/cat_move.js b/admin/themes/default/js/cat_move.js
index 709adb517..0abd41687 100644
--- a/admin/themes/default/js/cat_move.js
+++ b/admin/themes/default/js/cat_move.js
@@ -63,10 +63,14 @@ $(document).ready(() => {
     cont.find(".icon-folder-open, .icon-sitemap").addClass(colors[colorId]);  
   }
 
-  var url_split = window.location.href.split("&");
+  var url_split = window.location.href.split("#");
   var catToOpen = url_split[url_split.length-1].split("-")[1];
 
-  if(catToOpen) {
+  function isNumeric(num){
+    return !isNaN(num)
+  }
+
+  if(catToOpen && isNumeric(catToOpen)) {
     goToNode($('.tree').tree('getNodeById', catToOpen), $('.tree').tree('getNodeById', catToOpen));
   }
 
diff --git a/admin/themes/default/template/comments.tpl b/admin/themes/default/template/comments.tpl
index 6e0c351c2..9e21d7872 100644
--- a/admin/themes/default/template/comments.tpl
+++ b/admin/themes/default/template/comments.tpl
@@ -43,7 +43,8 @@ jQuery(document).ready(function(){
 });
 {/literal}{/footer_script}
 
-<h2>{'User comments'|@translate} {$TABSHEET_TITLE}</h2>
+<h2>{'User comments'|@translate}{if isset($TABSHEET_TITLE)} {$TABSHEET_TITLE}{/if}
+</h2>
 
 <div class="commentFilter">
   <a href="{$F_ACTION}&amp;filter=all" class="{if $filter == 'all'}commentFilterSelected{/if}">{'All'|@translate}</a> ({$nb_total})
diff --git a/admin/themes/default/template/group_list.tpl b/admin/themes/default/template/group_list.tpl
index 82781575c..8f75fe7e0 100644
--- a/admin/themes/default/template/group_list.tpl
+++ b/admin/themes/default/template/group_list.tpl
@@ -71,7 +71,11 @@ usersCache.selectize(jQuery('select.UserSearch'));
     </div>
     <div class="groupHeader">
       <div class="groupIcon"> 
-        <div class="icon-users-1 {$grp_color}"></div>
+        <div class="icon-users-1 
+    {if isset($grp_color)}
+      {$grp_color}
+    {/if}">
+        </div>
         <div class="groupMessage icon-ok"></div>
         <div class="groupError icon-cancel"></div>
       </div>
diff --git a/admin/themes/default/template/themes_installed.tpl b/admin/themes/default/template/themes_installed.tpl
index afca3f721..ba1ecb375 100644
--- a/admin/themes/default/template/themes_installed.tpl
+++ b/admin/themes/default/template/themes_installed.tpl
@@ -102,10 +102,10 @@ $(window).bind("load", function() {
     {assign var='version' value=$theme.VERSION}
   {/if}
   
-  <div class="themeBox{if $theme.IS_DEFAULT} themeDefault{/if}">
+  <div class="themeBox{if isset($theme.IS_DEFAULT) and $theme.IS_DEFAULT} themeDefault{/if}">
     <div class="themeShot"><a href="{$theme.SCREENSHOT}" class="preview-box" title="{$theme.NAME}"><img src="{$theme.SCREENSHOT}" alt=""></a></div>
     <div class="themeName" title="{$theme.NAME}">
-      {$theme.NAME} {if $theme.IS_DEFAULT}<i class="icon-star" title="{'default'|@translate}"></i>{/if} {if $theme.IS_MOBILE}<i class="icon-mobile" title="{'Mobile'|translate}"></i>{/if}
+      {$theme.NAME} {if isset($theme.IS_DEFAULT) and $theme.IS_DEFAULT}<i class="icon-star" title="{'default'|@translate}"></i>{/if} {if $theme.IS_MOBILE}<i class="icon-mobile" title="{'Mobile'|translate}"></i>{/if}
       <a class="icon-ellipsis-v showInfo"></a>
     </div>
     <div class="showInfo-dropdown dropdown">
@@ -125,7 +125,7 @@ $(window).bind("load", function() {
             <span class="dropdown-option icon-trash delete-plugin-button"title="{$theme.DELETE_TOOLTIP}">{'Delete'|@translate}</span>
         {/if}
       {/if}
-      {if $theme.DEACTIVABLE}
+      {if isset($theme.DEACTIVABLE) and $theme.DEACTIVABLE}
         <a href="{$deactivate_baseurl}{$theme.ID}" class="showInfo-dropdown-action tiptip icon-cancel-circled" title="{'Forbid this theme to users'|@translate}">{'Deactivate'|@translate}</a>
       {/if}
     </div>
@@ -136,7 +136,7 @@ $(window).bind("load", function() {
   {else}
         <div class="pluginUnavailableAction icon-cog tiptip" title="{'N/A'|translate}">{'Configuration'|@translate}</div>
   {/if}
-  {if not $theme.IS_DEFAULT}
+  {if isset($theme.IS_DEFAULT) and not $theme.IS_DEFAULT}
         <a href="{$set_default_baseurl}{$theme.ID}" class="tiptip icon-star" title="{'Set as default theme for unregistered and new users'|@translate}">{'Set as default'|@translate}</a>
   {else}
         <span class="tiptip icon-star" title="{'This is already the default theme'|@translate}">{'Set as default'|@translate}</span>
diff --git a/admin/themes_installed.php b/admin/themes_installed.php
index 7d92f5b82..2b6d3c173 100644
--- a/admin/themes_installed.php
+++ b/admin/themes_installed.php
@@ -146,7 +146,7 @@ function cmp($a, $b)
   if($a['STATE'] == $b['STATE'])
     return strcasecmp($a['NAME'], $b['NAME']); 
   else
-    return $s[$a['STATE']] >= $s[$b['STATE']]; 
+    return $s[$a['STATE']] <=> $s[$b['STATE']]; 
 }
 usort($tpl_themes, 'cmp');
 
diff --git a/admin/user_activity.php b/admin/user_activity.php
index cd70e4f12..948eefc1e 100644
--- a/admin/user_activity.php
+++ b/admin/user_activity.php
@@ -34,6 +34,12 @@ $template->assign('ADMIN_PAGE_TITLE', l10n('User Activity logs'));
 // +-----------------------------------------------------------------------+
 // |                          sending html code                            |
 // +-----------------------------------------------------------------------+
+$template->assign(array(
+  'PWG_TOKEN' => get_pwg_token(),
+  'INHERIT' => $conf['inheritance_by_default'],
+  'CACHE_KEYS' => get_admin_client_cache_keys(array('users')),
+  ));
+
 $template->assign_var_from_handle('ADMIN_CONTENT', 'user_activity');
 
 ?>
\ No newline at end of file
diff --git a/include/ws_core.inc.php b/include/ws_core.inc.php
index 845cd2a1b..cc3827394 100644
--- a/include/ws_core.inc.php
+++ b/include/ws_core.inc.php
@@ -584,7 +584,14 @@ Request format: ".@$this->_requestFormat." Response format: ".@$this->_responseF
     }
     
     $result = trigger_change('ws_invoke_allowed', true, $methodName, $params);
-    if ( strtolower( @get_class($result) )!='pwgerror')
+    
+    $is_error = false;
+    if (is_object($result) and strtolower( get_class($result) ) == 'pwgerror')
+    {
+      $is_error = true;
+    }
+
+    if (!$is_error)
     {
       if ( !empty($method['include']) )
       {
diff --git a/include/ws_protocols/json_encoder.php b/include/ws_protocols/json_encoder.php
index 641572537..b4b265d3b 100644
--- a/include/ws_protocols/json_encoder.php
+++ b/include/ws_protocols/json_encoder.php
@@ -10,8 +10,7 @@ class PwgJsonEncoder extends PwgResponseEncoder
 {
   function encodeResponse($response)
   {
-    $respClass = strtolower( @get_class($response) );
-    if ($respClass=='pwgerror')
+    if (is_object($response) and strtolower(get_class($response)) == 'pwgerror')
     {
       return json_encode(
         array(