Block Editor: allow block editor window to be moved if possible.

It would be nice to have if the Block Editor window could be moved around. Example - here I'm trying to describe a panel that's under the block editor so I can't see it.

<img width="1810" height="964" alt="Image" src="https://github.com/user-attachments/assets/ca5d7284-b7fd-4475-b319-a896bde02a46" />