add possibility to mark invoice sent by email without actually resending

[Luc De Ribeiro]

Hello,

When you edit an invoice for a minor change the sent by email sign disappears. Would be nice to be able to add the sign again without actually sending the invoice again.

PS: the version counter in the ticketing system is not up to date. I’m using the pro version bought on the mac app store V 1.8.4

Cordialement, best regards, schéi Gréiss,

Luc De Ribeiro