Afaik Constructs layouts are set up to only ever have one layout active at a give time.
What could possibly work is that whenever you detach a UI component, it launches a second instance of the project with the specific layout open. Then hook them up with a websocket somehow. But then again, Construct also suspends the engine when the window is out of focus, and it sounds like a bit of a nightmare to get working.
Second thing I can think of is that you just emulate what Construct itself is doing. I don't know the exact workings of it though.