a) As a sanity check add a direct transition that doesn't need button press and satisfy yourself it is the transition. In this config the email should send as soon as you load a record.
b)For the original transition, Edit & expand to all contexts. (It looks right now).
c) On your Workflow, expand it to all context also.
d) If that works you can tidy it up.
e) If it doesn't work then, hopefully someone else will spot the issue