I will use eM’s terminology in BOLD:
In my case, I have [email protected] set up as my DEFAULT ACCOUNT (starred) in «Menu:Tools:Accounts». For that default account, I have the Email field filled out with [email protected], which is an ALIAS of that account (both within the Gmail web interface and within eM Client’s list of aliases under «Menu:Tools:Accounts:Aliases…»).
And to be absolutely clear, I typed “[email protected]” into the Email field manually, not by selecting from the list of aliases that I had already added to «Menu:Tools:Accounts:Aliases…». Is this your only concern?
When I compose a NEW MESSAGE in eM Client 7 — whether the focus is on that Gmail account or any of the SMART or LOCAL FOLDERS — the email automatically defaults to [email protected] as the Send As address, without me having to manually choose it from the dropdown in the NEW MESSAGE window.
In other words, the alias [email protected] is my prefilled Send As address when I click the «+New» button (or use its associated SHORTCUT) while any of the SMART, LOCAL, or [email protected] folders are in focus.
[email protected] is not an ACCOUNT in the list of accounts in «Menu:Tools:Accounts».
So yes, from my point of view, I have an alias set up as my default sending address.
As you said, “The default address is only used in situation like when you are in Local Folders, or in another section of eM Client.” The alias [email protected] is the default sending address in these exact circumstances.
I have several other ACCOUNTS set up in eM Client, including an Outlook account and one other Gmail account. If the focus is on a folder for one of these accounts when I click the «+New» button, then obviously, the Send As address is not prefilled with [email protected], It’s instead prefilled with the address that is displayed in the Email field for the in-focus account in «Menu:Tools:Accounts».