Window is stuck under application menu bar

When opening Photoshop CS6 on my Mac, the Nik Collection tool auto opens and is stuck under the menu bar. When removing auto-open option, and manually opening it, it still appears in the same place. I tried restarting my computer as well as changing the screen resolution—nothing has helped.

See screenshot:

I was using an external (much larger) monitor prior, and then moved to a different location using the screen on my laptop—that's when this occurred. I tried reconnecting to the larger monitor again and trying all of the above, too—nothing helped either. One support forum suggesting shift-clicking and dragging the window, but all that did was resize the width and length; it didn't un-stick the top.

I'm on a MacBook Pro (Retina, 15-inch, Mid 2015); OSX El Cap v 10.11.6