A firm no has done nothing to change this.
Here's a really important bit of training advice....keep this in your mind, remember it. I'm not being flip here.
"NO" is not a command. Telling the dog "No NO NO" doesn't tell them what TO do. Same with using their name non-stop...."max Max MAX MAAAAX" doesn't give the dog a clue as to what they SHOULD do to make you happy. Dogs learn very quickly to ignore their name, and that's exactly what you DON'T want to happen.
I have a dog who was extremely sensitive to lights and shadows. After a friend saw her reaction to a flashlight (HI Christine!) she said we should be very careful about that. We were....we avoided using a flashlight around her, and if we saw her getting too focused on a shadow or light flash we distracted her right away. Did a recall and rewarded with a treat or toy, gave her something to distract her from the shadow. That dog is now quite elderly (14 years 8 months) and we STILL don't use flashlights right around her, tho we can be a lot closer since she can't see as well
--Regina and the GSDs:
UCDX von Sontausen Holy Grail (The BUNNY!) HGH, UD,RA,BN,GN, ASCA UD RAX High in Trial
PAM Monster Mike SchH2,UDX,OM1,TD,RE,VER
PAM FGDCh Ianna von Sontausen UDX,BH,TD,RE,PT (4.26.1998 - 2.11.2013)