Maybe I'm being dense, but I couldn't figure out how to color the background of the Room editor with your tool. It stays light gray.
Also, the little drop down arrows in the Room toolbar are always black and are hard to see with a dark theme, and I couldn't figure out how to change their color either.
Also, the little drop down arrows in the Room toolbar are always black and are hard to see with a dark theme, and I couldn't figure out how to change their color either.