Instructions for Gmail Extension for Salesforce to Log Emails:
https://sites.google.com/a/povertyactionlab.org/kb/home/salesforce
Troubleshooting:
I've been using SF in gmail for a while and I used to be able to use the "Log Email" or "Log Email on Send" buttons. Now they're both greyed out so I can't use that function (see screenshot). Do you know what's going on with that?
1. Send your response email and then go into my "sent" box and then attach using the "Log Email" function.
2. Here too you may find that the button is greyed out. Refresh the browser and the Log Email should be "blue" again.