For exemple enter 3 email addresses in a Compose window, then remove the middle one. Actually middle line stays empty. In my mind this line should be removed as in NS4.7.
Marking these all WORKSFORME sorry about lack of response but were very overloaded here. Only reopen the bug if you can reproduce with the following steps: 1) Download the latest nightly (or 0.9.6 which should be out RSN) 2) Create a new profile 3) test the bug again If it still occurs go ahead and reopen the bug. Again sorry about no response were quite overloaded here and understaffed.
Press the delete or backspace key again, and it's removed.