Remember my really long "roommate" thread from a couple years ago? Same person.

Because I live in a world that is far too small, she entered my graduate program this semester. I was not happy to (a) have to interact with her again or (b) have her in my intellectual space, but I had no choice. We have one class together; I am the head TA for the five sections of the class I'm in charge of (she teaches one section and thus I have had a slightly authoritative position over her); we are in the same large classroom-converted to office.

If you don't remember the story correctly, this is the roommate whose boyfriend spent too much time in our shared one-bedroom space and she yelled at me several times, once for something that I didn't do. She has a quick temper, is extroverted (I'm an introvert, and if you're an introvert too, you'll appreciate why that detail is important), and has some anger issues.

Because the yelling was very hurtful to me, when I knew we would be in a class together I went to the professor, informed her of the history, and told her that I was worried about the class being an emotionally safe place for me. She was receptive to my worries and agreed to not put us in any work or discussion groups together, etc. This class has gone OK, but I am facing another semester of having a class with her. This is a larger class and not a discussion one, but I have met with the professor and asked for the same arrangement - please don't put us in groups together, etc.

My current issue is that she is OBLIVIOUS to the boundaries I try to set for my office, and I don't know what to do. For example, one of the boundaries I have tried to set is "don't interrupt me when I am clearly doing work." [The office is an open space with desks - no cubicles though sometimes I REALLY want one]. She usually interrupts me when I am doing work and does not take the hint when I politely answer a question and then immediately look down/at my computer/get back to what I was trying to do. She is oblivious to this and usually keeps talking.

I am worried that in the class next semester she will ask me for help with homework (she asks me for help with her statistics homework now because I'm in a more advanced statistics class - and has not yet taken the hint of "I'm sorry, I'm busy doing _________ and can't help you").

My reasons for not wanting to interact with her: it is not so much fear of being yelled at again (I got over that in the beginning of this semester) but rather I don't enjoy interacting with her; furthermore, she was very hurtful toward me and with the way she treated me, I am not willing to spend time helping her. It's kind of like how you know there are "toxic" people in your life who just drain your energy, so you choose to set boundaries with them.

But what do you do when they are OBLIVIOUS to your boundaries? My latest tactic - she emailed me this morning and asked which of the two articles posted for class are optional. I wrote back "I don't remember [lie], check the assignment post." Current tactic: if I don't give helpful answers, she will eventually stop asking me questions.

Other ideas or thoughts? sorry for the long post.