I like @Northlight suggestion below to have a “Customised from address” option the dropdown without having to use the Shortcut keys “so it’s then obvious to the user”. I’ve added this idea to the current Sleekplan suggestion above
Shift + Ctrl + N for alias that will not be saved (or Delete key to remove the aliases that are no longer needed in the saved list)
Should CTRL+N & Shift + Ctrl + N be working yet on Mac ? Or is this in a future eM Client version with a different combo key ?