Hi Bill,
I'm so glad that the problem has been solved. I made a conclusion for this issue specifically, which may benefit other community members in the future.
Issue description:
You can't seem to dock the panel except the top. The panel will float anywhere in the Visual Basic window in Excel Mac.
Issue environment:
Excel for Mac
Issue solution:
You can try to uninstalland re-install Excel for Mac on your side via this article. Because re-install may reset some settings in Excel application.
Best regards,
Jazlyn