I've searched through all the similar posts I could find - each pretty much addresses a Windows box or never completes the thread, so I've not found an answer.
'09 iMac 24, CS6 (just updated), Software Update reports no needed updates (relative to the graphics card), etc.
When attempting to set up a lighting effect, the spot light displays but without control handles.
View->Extras is enabled (and toggling didn't help). Graphics card option was set to Basic, tried the others, no joy - and yes, the use graphics card option is also checked.
Any thoughts on what else could be causing the issue?
Could be a graphics driver problem/limitation. The lights handles are OK in Photoshop CS6 13.0.1 on my OS X 10.6.8 machine with NVIDIA GeForce 320M.
Which version of Photoshop is revealed by command Photoshop > About Photoshop... ?
What graphics card and which version of OS X do you have?
Some older threads that you could check: