I did see this question, but it was from two years ago, so I know it does not apply to my question.
Before the 10/1/2013 update, I was able to easily switch my sender email account to a different email address, but now, I can't. I have checked the settings in the app and for the email account.
Is there a setting somewhere in 4.6 that I am missing or did Google kill this feature for the mobile version?
If my question isn't clear, I apologize, and please let me know how I can improve it.
I'm using: Nexus 4, Android 4.3
After further investigation, it may be broken: gmail forum post