> virtual event # when the user selects an element. This event is generated after # the listbox is unposted (after you select an item, the combobox's # listbox disappears, then it is said that listbox is now unposted). themes_combo.bind("<>", self._change_theme) themes_combo.pack(fill='x') self.pack(fill='both', expand=1) def main(): app = App() app.master.title("Ttk Combobox") app.mainloop() if __name__ == "__main__": main()