User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:34.0) Gecko/20100101 Firefox/34.0 Build ID: 20141126041045 Steps to reproduce: 1. Open "New Message" window 2. start typing recipient name or address 3. choose one of the suggested recipients (other than the first one) 4. press TAB-key to move cursor to next field Actual results: If any other than the first recipient in the list of the suggested recipients is chosen, pressing TAB-key overrides the selected recipient with the first one in the mentioned list. Happens for me in thunderbird 31.3.0 but not in 31.0 Expected results: "To:"-field should contain selected recipient after pressing TAB-key. In thunderbird 31.0 (which I also tested) the cursor jumps to the next field automatically after selecting recipient from the list. Don't know why this changed in thunderbird 31.3.0