OJS 3.2 'List of the available themes' behaviour

Hello everyone!
In our OJS I’ve seen that the list of the available themes in the ‘Appearance’ tab of the ‘management/settings/website’ page shows a different list of themes from the list of activated themes you can find in the ‘Plugins’ → ‘Installed Plugins’ tab of the same page. For example, I’ve activated three themes, but in the ‘Appearance’ tab I can choose between seven of them. It’s that right? I’ve also checked the database and everything it’s fine, no strange record in plugin_settings table.

Looking into the code I’ve found that the list is returned by:
‘lib/pkp/classes/plugins/PluginRegistry.inc.php’ line 111:
$products = $application->getEnabledProducts('plugins.'.$category, $mainContextId);

which in turn uses:
‘lib/pkp/classes/core/PKPApplication.inc.php’ line 360
return $this->enabledProducts[$mainContextId][$category];

Thank you very much