title: Pressed button after leaving messagebox in tkinter
body: <p>In a binding to the button <code>DROP</code> function I have:</p>
  
  <pre><code>def on_click_button_drop(element):
  
      # ...
  
      if not db_name:
          print("db name empty")
          messagebox.showinfo("", "db name empty")
          return
  # ...
  button_drop.bind("&lt;Button-1&gt;", on_click_button_drop)
  </code></pre>
  
  <p>But after pressing <code>OK</code> in <code>messagebox.showinfo</code> the button left pressed...</p>
  
  <p><a href="http://prntscr.com/426xct" rel="nofollow">image 1</a>
  <a href="http://prntscr.com/426wcu" rel="nofollow">image 2</a></p>
  
  <hr>
  
  <p>Full test code</p>
  
  <pre><code>from tkinter import *
  import tkinter.messagebox as messagebox
  
  root = Tk()
  root.grid()
  
  
  def on_click_button_drop(element):
      db_name = entry_db_name.get()
      if not db_name:
          # print("db name empty")
          messagebox.showinfo("", "db name empty")
          return
      pass
  
  label_db_name = Label(root, text="db name")
  entry_db_name = Entry(root, width=20)
  button_drop = Button(root, text="DROP", width=10)
  
  label_db_name.pack()
  entry_db_name.pack()
  button_drop.pack()
  
  button_drop.bind("&lt;Button-1&gt;", on_click_button_drop)
  
  root.mainloop()
  </code></pre>
  
  <p>What to do to depress the button</p>