Index: branches/5.2.x/core/units/helpers/themes_helper.php
===================================================================
--- branches/5.2.x/core/units/helpers/themes_helper.php
+++ branches/5.2.x/core/units/helpers/themes_helper.php
@@ -594,15 +594,9 @@
 				// get theme, that user selected in catalog
 				$theme_id = $this->Application->RecallVar('theme_id');
 
-				if ($theme_id === false) {
-					// query, because "m_theme" is always empty in admin
-					$id_field = $this->Application->getUnitOption('theme', 'IDField');
-					$table_name = $this->Application->getUnitOption('theme', 'TableName');
-
-					$sql = 'SELECT ' . $id_field . '
-							FROM ' . $table_name . '
-							WHERE (PrimaryTheme = 1) AND (Enabled = 1)';
-					$theme_id = $this->Conn->GetOne($sql);
+				if ( $theme_id === false ) {
+					// Query, because "m_theme" is always empty in admin.
+					$theme_id = $this->Application->GetDefaultThemeId(true);
 				}
 
 				return $theme_id;