Python 3.3 TkInter window closes unexpectedly. Why? - python-3.x

Question

I came up with the following code more as a reference to help me remember how to build GUI apps with TkInter. It runs great except when a click Button1 or any other widget whose command option is set to self.hello. As you can see in the code bellow, the hello function is like a place holder. While the button click works fine while running the script through IDLE, it simply causes the application to exit if you start the program by double-clicking the actual file test.pyw. My question is, why?
#Some guy somewhere
from tkinter import *
class Application:
def hello(self):
msg = messagebox.showinfo('Message Title','Message Body')
def __init__(self, parent):
parent.resizable(0,0)
parent.minsize(800, 400)
parent.title('Top Level')
# Global Padding pady and padx
pad_x = 0
pad_y = 0
# CASCADE MENU
# create a parent menu.
self.parentmenu1 = Menu(parent, tearoff=0)
#self.menubar1.add_command(label='Menu1', command=self.hello)
#create a child menu for parent menu.
self.parentmenu1_child1 = Menu(parent, tearoff=0)
self.parentmenu1_child1.add_command(label='Item1', command=self.hello)
self.parentmenu1_child1.add_command(label='Item2', command=self.hello)
self.parentmenu1_child1.add_command(label='Item3', command=self.hello)
#add child menu to parent menu.
self.parentmenu1.add_cascade(label='Menu1', menu=self.parentmenu1_child1)
#self.menubar1.add_separator()
# SINGLE MENU
# create a parent menu.
self.parentmenu1.add_command(label='Menu2', command=self.hello)
# SINGLE MENU
# create a parent menu.
self.parentmenu1.add_command(label='Menu3', command=self.hello)
# display the parent menu.
parent.config(menu=self.parentmenu1)
# Create controls
#create label
self.label1 = Label(parent, text='Label1')
#create textbox
self.textbox1 = Entry(parent)
#create button
self.button1 = Button(parent, text='Button1', command=self.hello)
#string variable to hold checkbox1 values.
self.str_checkbox1 = StringVar()
#create checkbox
self.checkbox1 = Checkbutton(parent, text='Checkbox1', variable=self.str_checkbox1, onvalue='on1', offvalue='off1')
#deselect checkbox1
self.checkbox1.deselect()
#string variable to hold checkbox2 values.
self.str_checkbox2 = StringVar()
#create checkbox
self.checkbox2 = Checkbutton(parent, text='Checkbox2', variable=self.str_checkbox2, onvalue='on2', offvalue='off2')
#deselect checkbox2
self.checkbox2.deselect()
#???? ..what sets the groupbox apart from others. primary key???!!
self.str_radiobutton1 = StringVar()
#command= parameter missing.
self.radiobutton1 = Radiobutton(parent, text='Radio 1', variable=self.str_radiobutton1, value='a')
self.radiobutton2 = Radiobutton(parent, text='Radio 2', variable=self.str_radiobutton1, value='b')
self.radiobutton1.select()
#create a list of options.
optionList = ('Option1', 'Option2', 'Option3')
#string variable to hold optionlist values.
self.str_optionmenu1 = StringVar()
#associate string variable with optionlist
self.str_optionmenu1.set(optionList[0])
#create optionmenu
self.optionmenu1 = OptionMenu(parent, self.str_optionmenu1, *optionList)
#create a frame
self.frame1 = Frame(parent)
#create a text.
self.textarea1 = Text(self.frame1, width=20, height=10)
#align text left and fill frame with it.
self.textarea1.pack(side=LEFT, fill=Y)
#create a scrollbar.
self.scrollbar1 = Scrollbar(self.frame1)
#align scrollbar right and fill frame with it.
self.scrollbar1.pack(side=RIGHT, fill=Y)
#what is going to be scrolled?
self.scrollbar1.config(command=self.textarea1.yview)
#set textarea scrollbar.
self.textarea1.config(yscrollcommand=self.scrollbar1.set)
#align frame left and fill.
self.frame1.pack(side=LEFT, fill=Y)
#create a frame
self.frame2 = Frame(parent)
#create a text.
self.listbox1 = Listbox(self.frame2, width=20, height=10, activestyle='none', selectmode=SINGLE)
#create a list of items.
optionList = ('Item1', 'Item2', 'Item3', 'Item4', 'Item5', 'Item6', 'Item7', 'Item8', 'Item9', 'Item10', 'Item11')
#add items from list to listbox
for item in optionList:
self.listbox1.insert(END, item)
#align text left and fill frame with it.
self.listbox1.pack(side=LEFT, fill=Y)
#create a scrollbar.
self.scrollbar2 = Scrollbar(self.frame2)
#align scrollbar right and fill frame with it.
self.scrollbar2.pack(side=RIGHT, fill=Y)
#what is going to be scrolled?
self.scrollbar2.config(command=self.listbox1.yview)
#set textarea scrollbar.
self.listbox1.config(yscrollcommand=self.scrollbar2.set)
#align frame left and fill.
self.frame2.pack(side=LEFT, fill=Y)
# Place controls inside of grid
self.label1.grid(row=0, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.textbox1.grid(row=0, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.button1.grid(row=1, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.checkbox1.grid(row=1, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.checkbox2.grid(row=1, column=2, padx=pad_x, pady=pad_y, sticky=W)
self.optionmenu1.grid(row=2, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.frame1.grid(row=2, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.radiobutton1.grid(row=3, column=0, padx=pad_x, pady=pad_y, sticky=W)
self.radiobutton2.grid(row=3, column=1, padx=pad_x, pady=pad_y, sticky=W)
self.frame2.grid(row=4, column=0, padx=pad_x, pady=pad_y, sticky=W)
if __name__ == '__main__':
parent = Tk()
app = Application(parent)
parent.mainloop()

Answer 1

Alright. Apparently tkMessageBox has been renamed to messagebox in Python 3.x. Also this
module is not available in tkinter so even though a developer might use:
from tkinter import *
..he/she would still need to:
from tkinter import messagebox