I think that for users like me who are using keyboard shortcuts to open and close the panels, its unintuitive if they dont/hide show on the button press, regardless of whether the panel has been "pinned" or not. I would ask that you maintain that functionality in your new iteration, please! I use it constantly.
For what its worth, I liked the old behavior where tapping the icon on the bar would always toggle the panel, regardless of its pinned state.
It could be more visually clear that the panel is pinned, perhaps a thin outline around it or something to show that its in that state would be a simpler way to clarify how it will act.