Adding Tix Widget to Tkinter Container

Question

I'm working with Tkinter in Python 2.7 on Windows 7, and found the need to create a popup box with a tree-style list of checkboxes. I could not find this in Tkinter, or ttk. I did, however, find it in Tix in the CheckList widget. I got a working standalone example using Tix, but I cannot figure out how to add my Tix.CheckList to my ttk.Frame that controls my main program.

Surely I am not forced to use Tix framework from the ground up?

import Tix
import pandas as pd
import Tkinter as tk

class TreeCheckList(object):
    def __init__(self, root):
        self.root = root

        self.cl = Tix.CheckList(self.root)
        self.cl.pack(fill=Tix.BOTH, expand=Tix.YES)
        self.cl.hlist.config(bg='white', bd=0, selectmode='none', selectbackground='white', selectforeground='black', drawbranch=True, pady=5)

        self.cl.hlist.add('ALL', text='All Messages')

        self.cl.hlist.add('ALL.First', text='First')
        self.cl.setstatus('ALL.First', "off")

        self.cl.hlist.add('ALL.Second', text='Second')
        self.cl.setstatus('ALL.Second', "off")

        self.cl.autosetmode() 

def main():
    root = Tix.Tk()
    top = Tix.Toplevel(root)

    checklist = TreeCheckList(top)
    root.update()
    top.tkraise()
    root.mainloop()

if __name__ == '__main__':
    main()

The above code works in a standalone program using all Tix widgets. However, when I try to implement this into my larger program, I receive a TclError: invalid command name "tixCheckList"
To simulate this in the standalone, I changed the lines:

root = Tix.Tk()
top = Tix.Toplevel(root)

to

root = tk.Tk()
top = tk.Toplevel(root)

I was hoping I could just implement a Tix.Toplevel, placing it on a tk.Tk() root, but same issue.

Am I only allowed to use Tix frames when using a Tix widget, or am I misunderstanding something? If anyone has good Tix documentation, I would LOVE whatever I can get. It seems good docs on it are few and far between. Or is this same functionality included in ttk and I've just overlooked it? It seems to be one of the only things left out.

Answer 1

I have just learned that apparently only root needs to be a Tix class. Since Tk, and therefore ttk, classes appear to be added to the Tix root just fine (since most of them extend the Tkinter classes anyway), this appears to be a "fix". So my problem may have been solved by changing just

root = tk.Tk()

to

root = Tix.Tk()

This did require that I pull Tix into a part of my program I wasn't wanting for encapsulation purposes, but I guess there's no other way.