title: cv2.imshow image window placement is outside of viewable screen
body: <p>I am running Anaconda install of python35 with cv2 install from menpo.
  I am having trouble with <code>cv2.imshow()</code> inconsistently placing the image window outside of the viewable screen when running code similar to the one below both as a standalone script and line by line in the console (cmd, spyder, ipython)...</p>
  
  <pre><code>import cv2
  img = cv2.imread('Image71.jpg',0)
  cv2.startWindowThread()
  cv2.namedWindow('image')
  cv2.imshow('image',img)
  cv2.waitKey(0)
  cv2.destroyAllWindows()
  </code></pre>
  
  <p>I have also tried the above without <code>cv2.starWindowThread()</code> and <code>cv2.namedWindow()</code> with the same result. The window appears on my taskbar but is not in view, <code>cv2.waitKey(0)</code> responds to the keystroke, and I am not able to bring the window into view using any of the window arrangement shortcut keys for Windows 10 (e.g. alt+tab, Winkey + left, etc).
   My OS is Win10 version 1709. 
   Any help is much appreciated, thx!</p>