How do I move this window?

I was playing with my grandson in Photoshop & he made a wild swipe with the wacom pen & moved the tool box. Thing is, I can't seem to move it back! There doesn't seem to be a single spare pixel at the top which I can pick-up to move it. But he managed it without even trying! 🤣

(No, I haven't saved my workspace, sadly.)

The palette I use looks like this: