When I first looked at the error I suspected that maybe other upgrades were required as well so I did the following:
We are using HTML helpers.
I still get the error so I am at a loss as to what is causing it. Seems like a "base" or parent type is missing. Our project is very similarly setup to the JSFiddle so blah. What could it be?
Make sure you have reference to infragistics.ui.widget.js - cdn-na.infragistics.com/.../infragistics.ui.widget.js
I see the file in the modules directory. Why wouldn't the library automatically reference it?
Thank you for getting back to us.
The Infragistics.ui.widget.js file was introduced in version 17.2. As you noticed the script file is available in your installation directory and it has to be manually referenced if scripts are listed one by one. If the combined scripts are used then the file will be automatically included since it is part of the Infragistics.lob.js file.
Please let me know if you need any further assistance with this matter.