title: Icon with transparency on Windows 10 notifications
body: <p>I'm developing a Windows application (using Python &amp; the PyQt wrapper around Qt for the GUI), and extending the support for system-tray notifications.  Starting with Windows 10, specifying the "no icon" option (as opposed to information, warning or critical) displays the same icon as in the system-tray ... except with a solid-black background where the original is transparent.  I'd like the icon to render as specified (i.e. with a transparent background around the icon shape, over top of whatever "accent color" has been selected (automatically, based on the background color/image, or manually by the user).</p>
  
  <p>A full 50% of the search results I've gotten are reposts of "how to get rid of the 'upgrade to Windows 10' notification" ... which I applaud, but it's not what I need.  The nearest I've found here is a somewhat similar (and very old) post:
  <a href="https://stackoverflow.com/questions/387768/png-trayicon-transparency-on-windows">PNG TrayIcon transparency on Windows</a></p>
  
  <p>Given some of the other "hacking at your Windows 10 installation" articles I've come across, I'm hoping there's an undocumented registry setting I can utilize, since the same notification objects are happy to display the information/warning/critical icons with transparent backgrounds, just not my own application icon.
  <a href="https://i.stack.imgur.com/XisfE.jpg" rel="nofollow noreferrer">screen grab of Windows 10 notification with black-background image</a></p>