Include a drop-down list of "advanced categories operators" in search boxes

There is CDS webpage listing "advanced categories operators" (https://copernicsearch.freshdesk.com/en/support/solutions/articles/47001113420-refine-a-search-with-advanced-categories-operators).

I would be wonderful if a drop-down list like that could be accessed via a right-click from within any of the search-term boxes, from which an operator could be inserted in the search string being typed. The list should include a brief description of what each advanced operator does, since it otherwise would be hard to use.