We have a beta feature to give better value suggestions for properties that usually only use a small set of values like "sex and gender" or "driving side". Based on the on-of constraint defined on the property we show the expected value immediately in the value suggester.
Usually when middle-clicking on an entity in an entity selector it opens the entity in a new tab. (This is important if for some reason you are not sure if you have the right one and you want to investigate before choosing the entity and saving the edit.)
This behavior does not work for the suggestions from the beta feature.
- enable beta feature "Entity suggestions from constraint definitions" on https://www.wikidata.org/wiki/Special:Preferences#mw-prefsection-betafeatures
- start creating a new statement with property "driving side"
- see value suggestions "left" and "right"
- middle-click on one of the value suggestions
- see that nothing happens
- middle-clicking on the value suggestions opens the entity in a new tab