title: tkinter window changes size in zoomed state when made unresizeable
body: <p>I came across the problem that I want to have a (initially) fullscreen window which sometimes should be resizeable and sometimes not. But I found that (on windows) when I make it unresizeable it changes its size to fill the complete window including the taskbar which I don't want it to do. I want it to stay the size it initially was when I have set it zoomed (obviously).</p>
  <ul>
  <li>OS: Windows 10 Home</li>
  <li>Python: 3.7</li>
  <li>Tk/Tcl: 8.6</li>
  </ul>
  <p>Reproducable example:</p>
  <pre class="lang-py prettyprint-override"><code>from tkinter import Tk
  
  root=Tk()
  root.state('zoomed') #until here is everything normal
  root.resizable(False,False) #here taskbar gets hidden
  root.mainloop()
  </code></pre>