I have seen this kind of people at workplace (not in my group), the worst one has gone already, even though we knew she needed the job very badly.
If I were you, next time I would give her a written warning to “wake” her up. I have my bottom line, if a person’s negative behavior continuously affect my work and the whole team performance, I have to let him/her go, and everyone in the group needs to see this bottom line as well.
After all, making people leave is a tough decision, so usually I will find a chance to rotate this person to other groups to give him/her one more chance, but I’m not sure if you have a chance to do so.
Anyway, I understood your feeling very well, it is not easy to be a team leader.
Take care.
