Creating Add-Ins for Expression Web 4
Fortunately there is a tool called the “Add-in Builder” to help with that part. IT is available via the Expression Web blog. To further add in constructing add-ins, Erik Mikkelson has created a test harness that shows the outputs, errors, and events that arise from the extensions. He is referring to this tool as the Extensibility Tester.
York Xyander, Bodo Junglas Jul 31, 2015