User Agent: Mozilla/5.0 (X11; Fedora; Linux x86_64; rv:38.0) Gecko/20100101 Firefox/38.0 Build ID: 20150511091338 Steps to reproduce: Let's do it gherkin-style: Given that I have many similar addresses in your address book When I click on an address field And I move the cursor 10px down And I type the beggining of the email address And several addresses pop-up in the drop-down And the one I want is the first in the list and appears in the field And the cursor hovers another one And I press Enter Actual results: Then the resulting address should not be the one that was hovered Expected results: And the resulting address should be the one that was already in the field

I think thunderbird should not validate with the keyboard what was done with the cursor. I think more users follow the click then type then enter workflow than the click then select with the mouse then press enter workflow.

I like the gherkin-style... ;) Yes, that's a known issue, bug 1152517.

Woops! Sorry for that. Guess I did not have the good keywords…