When your first window loads in Tkinter it will generally appear slightly offset from the top left hand corner of the screen. This is a fairly counter intuitive location and most of the GUI driven programs that I run usually open at the center of the page or a little higher than center.
If you want a primer of window positioning, check out the following tutorial:
When you create your first window in Tkinter, you can set it’s starting size and position on the screen by using the geometry method.
When using this method, note that it only provides the window with the size and position when it is initialized. This means that the user can then change the size or the window and move it once it has first been put on the screen.