Used Office Partitions There Is A Partition On The Other Side Of My Office That Is Used For Visitors To Work At. There Is A Employee?

There is a partition on the other side of my office that is used for visitors to work at. There is a employee? - used office partitions

It offered office space, but decided to spend most of time. It is a nice person, but it makes me crazy. Listening to whistle type, just to be there. He took possession of my coffee and I can feel it in my personal space. I can not give personal or business phone lines and talk makes me nervous when you hear what I say.
He toured "MI office" a few times and grab things from my office. Nobody in this office.

Should I try it on purpose to annoy him, or what? I make music this morning.