When you have created a quote it would be useful to be able to search for a contact that the quote should be sent to. This contact may differ from the contact that is the parent of the quote.
When you click on the arrow to add an email address, this adds an additional email address to the contact that has already been set as the parent for the quote.
There should be an option to select a new contact that won't be automatically set as the parent.
It is possible to manually enter the email address once the compose email popup page is open, the one issue with this is that it is manual and it is possible to get the email address wrong when typing it in.