I know I clicked somewhere on my screen, but don't know what I did or how to correct it. The panes are now disconnected and can be moved and sized separately.
I use a laptop and a second screen. I use the 2nd screen for previews, but all else on the laptop.
Running Windows 10.
For some reason, I can't paste a screen shot into this post, so I've attached a pdf of the situation.
Thanks.