Accessing and responding to the open/close state of a sidePanel

[JeroenvdV]

Is there a way to retrieve the state of the extension's sidePanel: whether it is currently open or closed (in a certain tab)? Additionally, is there a way to listen to the event that this state changes?

Imagine I want to enable some functionality of a content script only when the sidePanel of the same extension is visible. Let's say showing the sidePanel makes the page's background color red, and closing the sidePanel reverts it back to normal.

I could send a message from the sidePanel's html page to the service worker, which will hopefully indicate that it has opened, but I don't know how I can respond to the user closing the sidePanel.