How do I change behavior of File Explorer taskbar button?

I've done this before, I'm confident I found the registry edit on this site, but can not locate it now after looking for hours.

Windows 8.1, I've enabled the [Quick Launch] toolbar with the guide on this site, and have created an icon for [File Explorer] on it. When you click on it, it launches Windows File Explorer, as you would expect. If you click on it again, it minimizes the window that's open, clicking again restores it. I want the Quick Launch shortcut to launch a New Separate Instance of Windows File Explorer, not just minimize or restore the one window.

I've done this before, I'm 90% sure it was a registry fix. To be clear, I am not looking to alter the function on the "Start Screen" tiles, and I don't want to have to hold another key while clicking. If I click the File Explorer icon 10 times I want 10 File explorer windows to open. I know it exists, I have just reached the end of patience trying to relocate the guide. I went through tutorials and searched google in 20 different ways and 10 pages deep, it wasn't this hard to find it before, similar to the Internet Explore tweak for the same result.

I just did a full reset to my system and want to re-tweak it before creating a new backup image.

Thanks for any instruction or a link to the existing guide.