Display vtkRendererWidgets

[Jørgen Cederberg]

Yi-Yu Chou wrote:
> Dear python users,
> 
> I tried to display 4 vtkRendererWidgets arrayed in a 2x2 grid.
> I method that I use is :
> 
> root = Tk()
> frame1 = Frame(root).pack(side=TOP)
> frame2 = Frame(root).pack(side=BOTTOM)

Here is your problem! The pack method returns None, such that frame1 and 
frame2 are None. Change it to:
frame1 = Frame(root)
frame1.pack(side=TOP)
frame2 = Frame(root)
frame2.pack(side=TOP)

<snip rest of program>

Regards
Jorgen