AFAIU, what @jmiba did was adding a new search suggest source, that provides search results when you use the live search from the top right corner of the page, while Loading... is about adding a new “Tags” facet to the main (standalone) search page. They’re not the same thing.
Searching tags case insensitive is asked several times by our users for both suggested search top right and search page itself. Fiddling with solr is outside my abilities.
I should like to state that I was also looking for case-insensitive tag-based search suggestions and have found that jmiba’s approach is the one that works.
In a different thread, it was proposed to simply copy the fields “tags_string” to “sort_string”.
Alas, this does not work, as “tags_string” is multivalued and sort_string is not.