Index: branches/5.2.x/core/kernel/application.php
===================================================================
diff -u -N -r16691 -r16716
--- branches/5.2.x/core/kernel/application.php	(.../application.php)	(revision 16691)
+++ branches/5.2.x/core/kernel/application.php	(.../application.php)	(revision 16716)
@@ -1,6 +1,6 @@
 <?php
 /**
-* @version	$Id: application.php 16691 2021-03-18 14:29:44Z alex $
+* @version	$Id: application.php 16716 2022-07-19 11:11:01Z alex $
 * @package	In-Portal
 * @copyright	Copyright (C) 1997 - 2009 Intechnic. All rights reserved.
 * @license      GNU/GPL
@@ -621,36 +621,38 @@
 	 */
 	public function GetDefaultThemeId($force_front = false)
 	{
-		static $theme_id = 0;
+		static $cache = array('force_front=yes' => 0, 'force_front=no' => 0);
 
-		if ( $theme_id > 0 ) {
-			return $theme_id;
+		$static_cache_key = $force_front ? 'force_front=yes' : 'force_front=no';
+
+		if ( $cache[$static_cache_key] > 0 ) {
+			return $cache[$static_cache_key];
 		}
 
 		if ( kUtil::constOn('DBG_FORCE_THEME') ) {
-			$theme_id = DBG_FORCE_THEME;
+			$cache[$static_cache_key] = DBG_FORCE_THEME;
 		}
 		elseif ( !$force_front && $this->isAdmin ) {
-			$theme_id = 999;
+			$cache[$static_cache_key] = 999;
 		}
 		else {
 			$cache_key = 'primary_theme[%ThemeSerial%]';
-			$theme_id = $this->getCache($cache_key);
+			$cache[$static_cache_key] = $this->getCache($cache_key);
 
-			if ( $theme_id === false ) {
+			if ( $cache[$static_cache_key] === false ) {
 				$this->Conn->nextQueryCachable = true;
 				$sql = 'SELECT ' . $this->getUnitOption('theme', 'IDField') . '
 						FROM ' . $this->getUnitOption('theme', 'TableName') . '
 						WHERE (PrimaryTheme = 1) AND (Enabled = 1)';
-				$theme_id = $this->Conn->GetOne($sql);
+				$cache[$static_cache_key] = $this->Conn->GetOne($sql);
 
-				if ( $theme_id !== false ) {
-					$this->setCache($cache_key, $theme_id);
+				if ( $cache[$static_cache_key] !== false ) {
+					$this->setCache($cache_key, $cache[$static_cache_key]);
 				}
 			}
 		}
 
-		return $theme_id;
+		return $cache[$static_cache_key];
 	}
 
 	/**