Hello,
I'd like to offer you some improvements to your Invoice Manager extension:

I have implemented extended Joomla access control features for your extension (see screen-shots).
As invoice data is quite sensitive data, I think this feature is a must have for your extension. Nobody wants to reveal invoice data to every employee who can access the backend.
If you're interested I could send you the Invoice Manager installation zip file including the access control feature code.



I've implemented independent access configuration for each section (Invoices, Quotes, Payments, ...) of the Invoice Manager extension, in order to maximize flexibility.
As you can see in the screen-shot below, this specific user has no permissions to create or delete invoices and therefore the buttons (and the code behind) is restricted.
Also in the menu tree to the left, only the allowed options for this user are available (no Quotes, Taxes, Templates,...)



In my opinion these additional features highly increase the value of your extension in real world scenarios.

I also wrote a complete language file translation to German (see screen-shot below). The complete user interface with all subcategories is translated (not only some strings, like in the language file you already offer).



If you're interested in the ACL features or the translation or both, just send me an email.

Regards,
Jan Weigel