Pi and I2C Expander won't add

I am using Raspberry Pi and cannot get an I2C extension to be used, I can see the address in I2Ctools. When I go to add the extension (MCP23008-E/P), the I.C. shows up on the right, under widget name but the Select Device pull down window doesn’t function which won’t allow it to be added. I tried a separate Pi from that project that doesn’t have any other devices on it to Cayenne but got the same results. Even tried different I.C. What am I missing to add a I2C expander to Cayenne?

use this GitHub - myDevicesIoT/cayenne-plugin-mcp23xxx: An MCP3XXX extension and PiFace Digital plugin for Cayenne

Awesome! thank you. I see it just auto-appears just like adding DS18B20 sensors.
BTW-I did a post in Slack so I will post there that it was solved with the Github link.