Unequivocally, the autohighlight behavior of the search box (disabled in build 12.0.512, as far as I can tell) is exponentially superior. IMO it should be changed back ASAP.
And, another change in the search behavior, where a search is performed within the present array based on previous selections from "View Items" in the "View Scheme" (like Artist, Rating, Album, etc.), is interesting but I'd like to know what people think about it.
Previously it would erase all your selections and perform a fresh search of the entire database.
I would suggest perhaps pressing ENTER with the cursor in the search box will perform a search of the entire database. Whereas not pressing enter will, as usual, search within the current array of results as the person types characters.
This saves the trouble of the user having to 1. realize no results have been achieved because the search was performed in a limited array, 2. position the mouse in the results window and double-click.
Pressing ENTER resets all View Items selections and returns results based on whatever is in the search box. This will be much faster than simply resetting first by pushing Alt+3 for example and then clicking in the search box and typing your characters. Alt+3 causes a delay while it fetches an array of ALL audio files in your database, which can be avoided by my suggestion.