Wrong edit mode for admin user if only override mode is allowed

Hello

If I enable only the override mode (in extconf), when I log in with an admin user, the edit mode dropdown show only "Override mode", which is good. But in fact, when saving, it is the extension file which is written, not the override file.

The issue is in \SGalinski\Lfeditor\Controller\AbstractBackendController::initializeAction. In this method, for admin user with an empty session, the default editing mode is set to extension, even if extension mode is not enabled in extconf.