Tkinter need to update a box based on whats typed in another box on another page
Solution 1:
You can solve this by importing GC and changing the function that is called when you click the template button to adding these few lines:
import gc
...
...
def load_page(self, controller):
controller.show_frame('template')
for obj in gc.get_objects():
if isinstance(obj, template):
obj.name_box.delete(0, tk.END)
obj.name_box.insert(tk.END, self.name_entry.get())