ColumnFilterWidgets extension page code samples not showing

I love this plugin. I am trying to figure out how to use the ColumnFilterWidgets extension, but the sample code on https://tablepress.org/extensions/datatables-columnfilterwidgets/ is not showing up. I used Google’s cache to figure that part out.

My shortcode looks like this;

[table id=1 datatables_columnfilterwidgets=true datatables_columnfilterwidgets_exclude_columns=1 datatables_columnfilterwidgets_max_selections=1 /]

My remaining question is how to get the dropdown to allow just a single choice AND to not remove options from the dropdown once they have been selected. I find it very strange that it does that. I think it would be much better for the dropdown to function like a normal dropdown. I suppose I may need to copy the extension and customize this myself … is that right?

The page I need help with: [log in to see the link]