When I open Lighting Effects in PS CC 2017 on my Late 2015 Mac desktop running Mac OSSierra 10.12.15 with AMD Radeon R9 M395 and graphics processor checked in PS preferences, I can access no control handles in the preview screen that appears no matter which preset or specific lights I select so I am unable to move and re-size these lights.
Just tried my Lighting Effects and noticed I had no handles too.
I tried View menu > Show > All and the handles came back. I did have to uncheck the grid in View > show, but all is well.
Mid 2012 MBP/OSX 10.12.5/CC 2017.1.1
See if that helps.
Thank you. Although Show All is now grayed out, and various other Show items selected, it now seems to work after I fooled around with Show choices a bit.
Thanks for letting us know. If someone else has the same problem, this at least will be one sure idea to try.