Good question, Nico.
Currently, the search switches from substring matching to the exact match when we place a comma between the categories. So it’s only possible to find multiple categories by one substring or find multiple exact matches (wiki: https://datagrok.ai/help/visualize/viewers/filters#search). @skalkin and @aydar.akhmetov can answer you if we are planning to implement this feature for our search.
There is a way to perform such filtering, though. You can do it with a free text filter (Filter menu | Add free text filter): the keyword “contains” looks for partial matches (case-insensitive, no quotes, e.g., dis_pop contains as or dis_pop contains uc
) and the “in” operator finds exact matches (case-sensitive, e.g., dis_pop in ("AS", "as", "UC")
). Here are the examples of such conditions along with the categorical filter:

This filter is not yet finalized, as far as I know, but it allows for more fluent filtering conditions, which you can already use.