title: Python 3 tkinter x scroll using arrow very slow
body: <p>In Python 3.x using a horizontal scrollbar and ttk treeview the x scroll by clicking on the arrows is very very slow, several pixels per second, I don't know how to fix this, here is a minimal example I made:</p>
  
  <pre><code>import tkinter as tk
  from tkinter import ttk
  
  app = tk.Tk()
  t = ttk.Treeview(app)
  t.pack(side="top",fill="both",expand=1)
  xscroll = tk.Scrollbar(app,command=t.xview,orient="horizontal")
  t.configure(xscrollcommand=xscroll.set)
  xscroll.pack(side="top",fill="x")
  
  tcols = ["header " + str(i)
           for i in range(50)]
  t.config(columns=tcols)
  for h in tcols:
      t.heading(h,text=h)
  
  for i in range(5):
      t.insert("","end",
               text = "item" + str(i),
               values = ["value" + str(x) for x in range(49)])
  app.geometry("{}x{}".format(800, 600))
  </code></pre>
  
  <p>it's the arrow clicking scrolling that is slow, the dragging using the bar is fine</p>