Just acquired this 4K Dell monitor and it's really annoying to have the LED power button on (intermittent light) when I shut down the PC.
Dell Team PLEASE come with an update to allow this setting (from below screenshot) when the PC is off.
(Why i need it? Because i have it in a room where at night I have a TV too right aside of monitor and every time i need to shut down the monitor from button because you can't watch at TV if a light is flickering!)
My two U3415W and UP3216Q also do this. This was a design choice made by the manufacturer. There are no settings to control the LED when in a non-active state. Dell is not going to create a firmware to change this design choice.