Steps to reproduce:

• Navigate to Wikibase SPARQL editor via Wikibase / Query Service link (e.g. https://iskouk-workshop.wiki.opencura.com/query/)
• Enter SPARQL query with custom prefixes e.g.:

PREFIX schema: <http://schema.org/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX iskouk: <http://iskouk-workshop.wiki.opencura.com/entity/>
PREFIX iskoukprop: <http://iskouk-workshop.wiki.opencura.com/prop/direct/>

SELECT * 
WHERE
{
  ?s iskoukprop:P2 iskouk:Q13 ;
    rdfs:label ?label ;
    schema:description ?description .
}

• Mouseover custom property (e.g. iskoukprop:P2)
• Observe no property or item pop up is shown (see
  
  ) but running the query gives the correct result
• Change prefix to wdt for property and wd for an item (e.g. wdt:P2 and wd:Q13):

PREFIX schema: <http://schema.org/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX iskouk: <http://iskouk-workshop.wiki.opencura.com/entity/>
PREFIX iskoukprop: <http://iskouk-workshop.wiki.opencura.com/prop/direct/>

SELECT * 
WHERE
{
  ?s wdt:P2 wd{F34766604}

{F34766605}:Q13 ;
    rdfs:label ?label ;
    schema:description ?description .
}

• Mouseover custom property (e.g. wdt:P2)
• Observe property and item pop up shown (see
  
  ) but running the query gives an empty result

What happens?:

No property or item pop up is shown when using custom prefixes in SPARQL query.

What should have happened instead?:

Custom prefixes for the property and item should be respected for displaying the property or item pop-up

Software version (if not a Wikimedia wiki), browser information, screenshots, other information, etc:

Product - Version
MediaWiki - 1.35.3 (f921256) 10:08, 2 September 2021
PHP - 7.4.23 (apache2handler)
MariaDB - 10.3.22-MariaDB-log
ICU - 67.1
Lua - 5.1.5
LilyPond - 2.22.0

Wikibase
Extension - Version - Licence - Description - Authors
EntitySchema - – - GPL-2.0-or-later - Store and discuss Schemas for Wikibase entities - The Wikidata team
Wikibase EDTF - 1.2.0 - GPL-2.0-or-later - Adds support for the EDTF standard to Wikibase via a dedicated data type - Jeroen De Dauw and Professional.Wiki
WikibaseClient - – - GPL-2.0-or-later - Client for the Wikibase extension - The Wikidata team and others
WikibaseManifest - 0.0.1 - GPL-2.0-or-later - Combines metadata about a Wikibase installation exposing it as a simple API - The Wikidata team
WikibaseRepository - – - GPL-2.0-or-later - Structured data repository - The Wikidata team and others
WikibaseView - – - GPL-2.0-or-later - View component for the Wikibase Repository - The Wikidata team and others