datagrid extension widgets and no constructor found

I am trying to use the Datagrid Extension widget and getting no constructor errors. Top message is for the Datagrid Extension with context, bottom is for the widget without context.

I've tried clearing my cache, restarting the browser and cleaning the deployment directory but it's still not working.  I'm using Modeler 6.10.4 and trying to run locally.

No constructor found for widget DataGridExtension.widget.DataGridExtension

Could not create widget DataGridExtension.widget.DataGridExtensionNoContext