Taxonomies search widgte vs filters

Using the Taxonomy Search widget appears to dive me a list of taxonomys including those defined by WordPress and other plug-ins, but not taxonomys created through MTDF. However the Add Filter only comes up with Taxonomies created through MDTF. Same when I try to assign a page to a category; So which taxonomies are you using.

Would it help if I replicated standard taxonomies as MDTF taxonomies…would the search pick these, up?

Yours confused, Phil

PS: I will purchase the Code Canyon version once I;ve proved that the free version meets my needs.

https://wordpress.org/plugins/wp-meta-data-filter-and-taxonomy-filter/