To sum up, in SIERRA :

1. sometimes I will get the popup with Dictionaries, Wiki, Apple, etc. (per joemikeb #42524)

2. sometimes I will get the popup with “No Results Found” message (per Artie505 #42528)

3. sometimes I will get no popup or any message of any kind (per joemikeb #42524)

grin grin

So it appears to me, that this feature is working completely as expected in SIERRA . . . with some minor adjustment of the 3-finger(s) position at times.

Many thanks,
MG2009