Secondary Monitor, no dimming

[#1]

Hola!  I just discovered an issue that wasn't there before . . .  I run my laptop to an external monitor.  In the past, I would just connect, click the secondary monitor symbol and hit "L" to dim the secondary monitor.  Not anymore.  Now, the display to my laptop dims but not the external monitor and I need it to go back to where the external monitor dims and not the laptop display.  Anymore?  Thank you in advance!

[#2]

Hola!  I just discovered an issue that wasn't there before . . .  I run my laptop to an external monitor.  In the past, I would just connect, click the secondary monitor symbol and hit "L" to dim the secondary monitor.  Not anymore.  Now, the display to my laptop dims but not the external monitor and I need it to go back to where the external monitor dims and not the laptop display.  Anymore?  Thank you in advance!

[#3]

I am trying to figure out your issue...testing it.