Cannot remove default invoice "confirmed" state

[lostika]

I dont want to send invoices in emails on order state change. So I wanted to remove the 'confirmed' state from the configuration panel (Default Order Status to create an invoice), after saving the settings, confirmed state still there no matter what I do 
Does it a bug? Or config needs one status to choosed?
Joomla! 3.4.1, VirtueMart 3.0.6 ...