"From" address in response draft editor automatically selects incorrect address.

[RokeJulianLockhart]

1. Prerequisites

   1. I have searched open and closed issues for duplicates
   2. This isn't a feature request
   3. This is not a report about my app not working as expected

2. Issue

   As Why are my responses being sent back to me? anonaddy/anonaddy#613 (comment) explains, when I am sent a message from an external service which modifies the From address to be a variant of an existent ProtonMail alias of mine, the response form automatically selects that alias:

   

   I want to be able to control whether it does this — sometimes it's desirable, other times not. How can this be overridden? It's somewhat of a security concern in retrospect.