title: Tkinter KeyPress and KeyRelease events
body: <p>I understood that the Tk keypress and keyrelease events were supposed only to fire when the key was actually pressed or released?</p>
  <p>However with the following simple code, if I hold down the &quot;a&quot; key I get a continual sequence of alternating keypress/keyrelease events.</p>
  <p>Am I doing something wrong or is TkInter buggy? This is Python2.7 on Linux mint.</p>
  <pre><code>from Tkinter import *
  def keyup(e):
      print 'up', e.char
  def keydown(e):
      print 'down', e.char
  
  root = Tk()
  frame = Frame(root, width=100, height=100)
  frame.bind(&quot;&lt;KeyPress&gt;&quot;, keydown)
  frame.bind(&quot;&lt;KeyRelease&gt;&quot;, keyup)
  frame.pack()
  frame.focus_set()
  root.mainloop()
  </code></pre>
  <p>Output when pressing and holding &quot;a&quot;:</p>
  <pre class="lang-none prettyprint-override"><code>down a
  up a
  down a
  up a
  down a
  up a
  down a
  up a
  etc...
  </code></pre>