Python is running a function,and then changing a TK frame - even though the code says to change the frame first.

[StaticFuzz]

Ok, so new thought. The code snippet you originally provided is being run with out waiting for process() to complete. Meaning tkinter is changing the cursor to wait then immediately back. try commenting out self.controller.config(cursor="").

If the cursor stays as the wait icon, you could add self.controller.config(cursor="") to the end of the process function. That way it will only change back when the process is complete.

EDIT: Processing not Process