When the lines that are shown in the results of a query in WDQS that use #defaultView:Tree are clicked, the Wikidata items that correspond to those lines are not opened. I think a more useful behavior would be to open the Wikidata item when the line is clicked since users could see all the information that is stored in Wikidata about that that item.

Try executing the minimal working example below in WDQS (link here)

#defaultView:Tree
SELECT ?a ?aLabel ?b ?bLabel {
  VALUES (?a ?b) {
    # Wikipedia / Spanish Wikipedia
    (wd:Q52 wd:Q8449)
    # Wikipedia / English Wikipedia
    (wd:Q52 wd:Q328)
    # Wiktionary / Spanish Wiktionary
    (wd:Q151 wd:Q33108860)
    # Wiktionary / English Wiktionary
    (wd:Q151 wd:Q22001375)
  }

  SERVICE wikibase:label { bd:serviceParam wikibase:language "en". }
}

If you try to click in any of the lines of the results of the query shown above, the Wikidata items corresponding to those lines are not opened.

As I mentioned, I think a more useful behavior would be those entities to be clickable just as happens in #defaultView:Graph or #defaultView:Map.