improvement: dynamically activate all installed themes (with checks on

parent availability and so on).

git-svn-id: http://piwigo.org/svn/trunk@5340 68402e56-0260-453c-a942-63ccdbb3a9ee

admin/include/themes.class.php

@@ -81,6 +81,12 @@ class themes
           break;
         }
 
+        if ('default' == $theme_id)
+        {
+          // you can't activate the "default" theme
+          break;
+        }
+
         $missing_parent = $this->missing_parent_theme($theme_id);
         if (isset($missing_parent))
         {