tkk checkbutton appears when loaded up with black box in it

I've had a similar issue on Windows 7.

After loading the app, one of my checkbuttons contained a filled square. But after clicking on it, it became a normal checkbutton:

In my case, it was because I had multiple checkbuttons sharing the same variable... After creating a separate Tk.IntVar() variable for each checkbutton, the problem disappeared.

import Tkinter as Tkimport ttkroot = Tk.Tk()checkVar = Tk.IntVar()x = ttk.Checkbutton(root, variable=checkVar, text="check 1")x.pack()checkVar2 = Tk.IntVar()y = ttk.Checkbutton(root, variable=checkVar2, text="check 2")y.pack()root.mainloop()

I hit this problem when creating a Checkbutton object from within a class. I was declaring a local variable instead of a member variable in the class. The local variable was getting out of scope causing the checkbox value to not be either a 0 or a 1.

Wrong:

    import tkinter as Tk    from tkinter import IntVar    from tkinter.ttk import Frame, Checkbutton    class TestGui(Frame):        def __init__(self, parent):            Frame.__init__(self, parent)            var1 = IntVar()            var1.set(1)            button = Checkbutton(parent,                text="Pick me, pick me!",                variable=var1)            button.grid()    root = Tk.Tk()    app = TestGui(root)    root.mainloop()

Fixed:

import tkinter as Tkfrom tkinter import IntVarfrom tkinter.ttk import Frame, Checkbuttonclass TestGui(Frame):    def __init__(self, parent):        Frame.__init__(self, parent)        self.var1 = IntVar()        self.var1.set(1)        button = Checkbutton(parent,            text="Pick me, pick me!",            variable=self.var1)        # note difference here        button.grid()root = Tk.Tk()app = TestGui(root)root.mainloop()