Should I give this person the 'boot' or how to deal with it?

[Dave Fairb]

I have a house that I live in, I live on the middle floor and rent to 3 people upstairs. Air Bnb in basement. 

My middle floor is mostly private from upstairs, but, as far as the landlord tenant act is concerned we 'share' the space. And as such it's considered 'roommates'. 

There's one person upstairs who has lived here for 5 years. Originally she told me she was a student from Korea. She'd answered an ad I had on a bulletin board for international students. 

5 years later and she's still living here and still a student? And I've learned that she's a young looking 40 years old, and the cut off for international students visas is 32. So she probably never did fit into the category of international student in the 5 years she's lived here. 

When she first moved in, she had a guy bringing her bags and boxes up the stairs. I later found out that she'd had been living just a few blocks away. The guy carrying her boxes was her boyfriend as she put it , and that she's been living in a share house situation with him. He was another renter there and was in a relationship with the homeowner. But the 2 of them had had an affair and the homeowner kicked her out when she found out. Boyfriend moved away to east coast soon after. 

So for the last 5 years she's paid her rent and been cordial but somewhat standoffish. That's OK, it doesn't have to be anything other than that. 

About a year ago, 2 of the other student renters when leaving told me that they found her to be quite cold towards them. Which I noted. 

Then I noticed she was leaving 'notes' for the others telling them to do this and that around the kitchen. 

About 3 months ago I heard this heck of a banging noise coming from upstairs. So I went up and she was furiously pounding on one of the other roommates door. The other roommate was doing an online class at the time. 

When I asked what was going on, she told me that the roommate had put the toilet plunger in the wrong place, so she had put the plunger on the bathroom counter next to the girls things (gross) , and the girl had put it back in the 'wrong' place again on purpose!? So she went ballistic and hammered on the door. 

OK, so I got things calmed down and the other girl had already given notice to move, maybe because of Korean Roommate? It's not clear. 

But now I was having my serious doubts about the Korean women. 

I had to talk to her about something else. She had been leaving her bedroom window open all last winter when she was out, she says for fresh air. So it was January below freezing and her window was open and the heat on, and it's electric baseboard heat, expensive. So I talked to her about it, and in a reasonable and professional manner. She shot me these glaring dirty looks. And I had to really press to get her to say that she'd agree to keep it closed. 

I also checked the baseboard heaters at that time and noticed she had plastic drawers and a cardboard box right up against the heater. I told her she cannot do that! It's a fire risk, and again repeated 'why' it's a bad idea and that she cannot do it. 

But I noticed as of last week she didn't move them. 

I had to talk to her about something else and she just ignored me, looked at her computer and just blanked me. I was shocked. I just looked at her and said "Oh, I see. I understand" and I got up and went downstairs. 

I've seen her once since then, it was outside in the garden and it was just 'hello' from both of us. 

It's got now that if she hears me coming upstairs she seems to quickly leave the kitchen up there and head to her bedroom. For me I feel uncomfortable going up there. 

Her rent is a deal for her and no way would she rent a room for what she's paying, and I've been really quite reasonable. 

Not sure what to do for best. 

Edit

I should add to this, that as it's a roommate situation, I have a no 'boyfriends over' rule. But she was very nice in asking if I'd make an exception for her to have her new boyfriend over once every now and then. Which I agreed to as she'd asked in a reasonable way at the time. 

I'm seeing this pattern of her being charming when she wants something, a (Beep) when she doesn't like something, and she's kept her head down for 5 years and has only had 2 small rent increases and has a deal.