Add-on overlaps source in demo

[javier-godoy]

I can't read the sources because the chatbot is displayed on top of them.

[javier-godoy]

We'll address this by FlowingCode/CommonsDemo#72

[mlopezFC]

Okey, but also take into account that you can minimize the chat window so you can see the underlying code if it is needed. I thought about implementing a feature to choose the location of the chatbot but it is not easy and maybe too much effort just to see the code while it is not minimized so I disregarded it.