Follow-up from "Fix the reply an edit text being shown in all chat rooms when multiple windows are open"

The following discussion from !496 (merged) should be addressed:

• @miepee started a discussion: (+4 comments)

  Hm, something I noticed is that the chatbox content is shared if both the main window and detached window have the same room Setup:

  • Have room A on main window

  • Open room A in detached window

  • Type in chatbox of main window

  • Notice that what you typed magically appears in detached window

  • Type in chatbox of detached window

  • Notice that what you typed magically disappears once focus is lost, to match chatbox contents of main window