I copied your esearch widget folder and changed the config.json to the one that I have downloaded from my web application. My widget folder name is cfsSearch. I changed some things in the setting.js, manifest.json and Widget.js (anything that had esearch in the name, I've changed to cfssearch, based off of baseClass: 'widget-cfssearch').
When I try to add the widget, it's bringing up a duplicate one and is giving me the following error. Can you shed some light on this please?