That does not work because Idle just moves the window down to compensate. (It seems to take two openings to have that happen.) 

Even if that worked, I would still ask why I should have to make the window smaller, when I want it larger (44 lines), located where I want it (all visible). Why can't Idle act like a well-behaved Window app? Saving the last Window position and size is fairly common. In any case, Edit windows are opened near the top of the screen, as they ought to be, instead of almost touching the bottom.