I just wanted to add my support to this request. I would be very interested in this search as a way to allow users to figure out, if they appear on 'have i been pwed', exactly which account on which website a breach came from. It would also allow users to create new passwords that have never been used anywhere, ever.
There is a feature that limits the number of historical versions that are stored for each individual record. Check your settings... File > Database Settings > Advanced Tab to see if this isnt the case.
To enable it within the toolbar search, go to... Tools > Options > Interface tab, scroll down to Quick Search (Toolbar) section and tick the first box; 'Search for passwords in quick searches'