Thank you so much, this was driving me nuts. I guess that all users across the world just stop using search because of how it is out of the box. All heuristics dictate that multichoice default cannot be the weird choice AND an unchangeable. This is a drastic oversight by developers, no doubt.
This review is for a previous version of the add-on (1.12).
It's a sad time though, in which one must write an extension to get the basic behaviour, the one where the system doesn't have the presumption of deciding what's relevant for the user, with ever more sophisticated and intransparent pseudo-"intelligent" behaviour crippling the things we use every day.
This review is for a previous version of the add-on (1.11).