Python OptionMenus keep disappearing and reappearing - how can I make them "stay"?

Question

I have a simple school assignment to do - a converter between F, C and K. I'm having problems with OptionMenus, because they keep disappearing and reappearing when I move over with the mouse. For example if I choose from OptionMenu2, OptionMenu1 will disappear. How can I make them "stay"?

Code includes 2 pictures. If you want to run the code, you'll need one for button. You can probably just delete the one on top :)

I'll appreciate any help on this!

# -*- coding: cp1250 -*-

from Tkinter import *
import tkMessageBox
import tkFont
from array import *
from decimal import Decimal 


class MojGUI(Frame):
    def __init__(self, master=None):
        Frame.__init__(self, master)

        ##NASLOV
        image1 = PhotoImage(file="naslov.gif")
        panel1 = Label(root, image=image1,background="#FFFFFF",height=50,width=400)
        panel1.pack(side=TOP)
        panel1.image = image1

        panel2 = Label(root,background="#FFFFFF")
        panel2.pack(side=TOP)
        self.vnesibesedilofont = tkFont.Font(family="Verdana",size=16,weight="bold")

        ##VPIS CIFRE
        self.entryfont = tkFont.Font(family="Verdana",size=14,weight="bold")  
        self.entryWidget = Entry(panel2, width="4",font=self.entryfont,foreground="#FFFFFF", background="#bb0000")
        self.entryWidget.pack(side=LEFT)

        ##ENOTA1
        self.text1 = StringVar(master)
        self.text1.set("C") # default value
        self.enota1 = OptionMenu(panel2, self.text1, "C", "F", "K")
        self.enota1.pack(side=LEFT)

        ##ENACAJ
        self.enacaj = tkFont.Font(family="Verdana",size=16,weight="bold")
        self.znak = StringVar()
        self.znak.set(" = ")
        self.entryLabel = Label(panel2,textvariable=self.znak, background='#FFFFFF',font=self.enacaj)
        self.entryLabel.pack(side=LEFT)

        ##VREDNOST
        self.textvrednost = StringVar()
        self.vredno = tkFont.Font(family="Verdana",size=14,weight="bold")
        self.vrednost = Label(panel2,textvariable=self.textvrednost, width="9", foreground='#000000',background='#FFFFFF',font=self.vredno)
        self.vrednost.pack(side=LEFT)
        self.textvrednost.set("")

        ##ENOTA2
        self.text2 = StringVar(panel2)
        self.text2.set("C") # default value
        self.enota2 = OptionMenu(panel2, self.text2, "C", "F", "K")
        self.enota2.pack(side=LEFT)

        ##GUMB
        image2 = PhotoImage(file="pretvori.gif")
        entryButton = Button(panel2,text="",bd="0",cursor="hand2",background='#FFFFFF',activebackground="#FFFFFF",command=self.pretvori,image=image2)
        entryButton.pack(side=LEFT)
        entryButton.image = image2

        self.pack()

    def pretvori(self):

        enota1=self.text1.get()
        enota2=self.text2.get()
        original=Decimal(self.entryWidget.get())
        rezultat= StringVar()
        rezultat.set(str(original))

        if (enota1 == "C") &(enota2 == "K"):
            rezultat.set(str(round(original+273,2)))

        if (enota2 == "C") &(enota1 == "K"):
            rezultat.set(str(round(original-273,2)))

        if (enota1 == "K") &(enota2 == "F"):
            rezultat.set(str(round( Decimal(original-273) * Decimal(1.8)+32 ,2)))

        if (enota2 == "K") &(enota1 == "F"):
            rezultat.set(str(round( Decimal(original-32) / Decimal(1.8)+273 ,2)))

        if (enota1 == "C") &(enota2 == "F"):
            rezultat.set(str(round(original*Decimal(1.8)+32,2)))

        if (enota2 == "C") &(enota1 == "F"):
            rezultat.set(str(round((original-32)/Decimal(1.8),2)))

        self.textvrednost.set(rezultat.get())
        self.znak.set(" = ")

root = Tk()

root.title('Pretvornik')
root.wm_minsize(500, 200)
root.wm_resizable(0, 0)
w = root.winfo_screenwidth()
h = root.winfo_screenheight()
rootsize = tuple(int(_) for _ in root.geometry().split('+')[0].split('x'))
x = (w - 500)/2
y = (h - 200)/2
root.geometry("%dx%d+%d+%d" % (rootsize + (x, y)))
root.config(background="#FFFFFF")
app = MojGUI(master=root)
root.mainloop()

Answer 1

You are doing something very unusual when you use a label as a container for other widgets. The label is not an appropriate widget to use as a container for other widgets. While this should be allowable, it apparently is causing the behavior that you are seeing. If you change panel1 and panel2 to be frames rather than labels, your problem goes away.