RE: Would I be able to do this with “Enhanced Categories“?
Sorry, the Enhanced Categories add-on would not affect the Categories Widget’s use of the fragment cache optimization.
I just pushed an update to the widgets, version 2.12. I’ve implemented a filter that can be hooked into to disable the fragment cache for the Categories widget.
Install and activate the Code Snippets plugin. Add and activate a new code snippet with the following code to disable the Categories widget fragment cache:
add_filter(
'Connections_Directory/Widget_Pack/Widget/Category/Use_Fragment_Cache',
'__return_false'
);
With this code snippet active and the CSS code I supplied earlier, the active category will be highlighted.
I hope this helps; please let me know.