The behavior is a bit arbitrary, yes, but that's entirely intentional. I find it somewhat baffling that you'd want windows to open in the middle of the screen, as that would obscure the character, making it harder to click other objects in the vicinity without having to move the windows out of the way first. If anything, the client goes out of its way to try and not auto-place windows on top of the character. The reason different things open in different places is just so that windows from different things try to not conflict with each other.
MagicManICT wrote:I hate how when I open three cupboards to move things around I have to move the cupboard windows around first.
Not sure what you mean by that either. When I open three containers, the client tends to properly put their windows side-by-side, exactly so that they don't have to be moved out of the way of each other.