Hi there,
That is correct! You can drag it after opening and it will stay on the screen for you to use when in the editor.
Regarding the resize element, this was also mentioned on another post (here: TOC panel/window resizable please ) and it is an interesting idea.
As mentioned over there too, we’d have to weigh up the design and consistency aspects with the user interest for this and see where it takes us.
But i’ll pass it onto the team to consider!