In Unity a left or right click opens the file so that option isn't
possible any more. Suspect that the way around it is to install an
alternative file manager that does searches in the 'old way'. Maybe
Dolphin, the KDE one ?

FWIW this is one reason I felt Unity wasn't for me even though I love
the simplicity for less demanding users and I have several customers
using it without problem. My needs were more than Unity could offer.