Symbol word already in category

Hi, when looking for a word, the symbol + in a square appears in the search result if a word is already in a category. It used to also appear in the list of “words containing”: is it an option to activate, or is it something missing? I think it is very useful when opening the card of a character to quickly see all the words learned that contain it. Thanks! Pierre
 
Very strange it seems to work for some but not all. For instance for 友 it shows the symbol for the “synonym” 我 and the “antonym” 敌, but not for “word containing” 朋友 for instance.
 
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