Hi Graeme,
I had wondered if it might be a python2 vs python3 thing. It was. Thanks for the prompt.
Linux Mint 19.2, out-of-the-box, appears to be incomplete with respect to what is needed to install and run python3 Quisk. I had been running python 2.7 because that was the default in the distribution. Today, I installed the missing bits for python 3 and then the python 3 version of Quisk using pip. That seems to have fixed the "ON" button behavior.
To install and run the python 3 version of Quisk did require installation of several packages. It was an onion pealing process. Here's a list from /var/log/apt/history.log for today:
python3-pip
python3-setuptools
python3-dev
libpython3.6-dev
dh-python
libpython3-dev
python3.6-dev
python3-sip
python3-wxgtk4.0
python3-usb
Bruce, ag5gt
