title: Modifying treeview column width after creation
body: <p>I want to use the same tree widget for different reports. To make this work I need to modify the header every time before inserting new data. But I can't get the widget to behave the way I want it to: whenever I change the header/width, an empty column will come out of nowhere. Is there something I can do to prevent that or I must destroy and recreate a new treeview everytime?</p>
  
  <pre><code>import tkinter as tk
  from tkinter import ttk
  
  root = tk.Tk()
  tree = ttk.Treeview(root, selectmode='browse')
  tree.grid(row=0,column=0)
  tree_header = ("One", "Two", "Three", "Four", "Five")
  tree_width = (100, 100, 100, 100, 100)
  tree["columns"] = tree_header
  tree['show'] = 'headings'
  
  for i in range(len(tree_header)):
      tree.column(tree_header[i],width=tree_width[i], anchor="w", stretch = False)
      tree.heading(tree_header[i], text=tree_header[i], anchor='w')
  tree.insert("",tk.END,text="",value=(1,2,3,4,5))
  
  def click_me():
      tree.delete(*tree.get_children())
      new_header = ("Six","Seven","Eight","Nine","Ten")
      new_width = (120, 80, 120, 80, 100)
      tree["columns"] = new_header
      tree['show'] = 'headings'
      for i in range(len(new_header)):
          tree.column(new_header[i],width=new_width[i],anchor="w", stretch = False)
          tree.heading(new_header[i],text=new_header[i],anchor="w")
      a_button.config(command=click_me_again)
      tree.insert("", tk.END, text="", value=(6, 7, 8, 9, 10))
  
  def click_me_again():
      tree.delete(*tree.get_children())
      tree["columns"] = tree_header
      tree['show'] = 'headings'
      for i in range(len(tree_header)):
          tree.column(tree_header[i],width=tree_width[i],  anchor="w", stretch = False)
          tree.heading(tree_header[i], text=tree_header[i], anchor='w')
      a_button.config(command=click_me)
      tree.insert("", tk.END, text="", value=(1, 2, 3, 4, 5))
  
  a_button = tk.Button(root,text="Click me",command=click_me)
  a_button.grid(row=1,column=0)
  
  root.mainloop()
  </code></pre>