...in the Designer and on an emulator these are the controls associated with the above Blocks
and this link shows the same app on a device Chat app message style - #20 by SteveJG might be helpful.
The Button1 and Textbox2 are 'hidden' within an arrangement that is normally invisible until the Button4 (Create New Room) is used to toggle HorizontalArrangment visible/hidden.
You might do something similar with your chat app. Hope this is useful.