Anything missing?

Hi,
I’ve been looking at the demo and this problem keeps appearing.

I’ve python 3.7 installed and wxpython 4.04. They both appear

to be up to date. Is there some other package required?

Also, it’s on a Mac, Sierra 10.12.6.

Thanks

Mel

Screen Shot 2019-03-24 at 5.34.40 PM.png