Sorry for delay
Am studying your various reports
Just looking at the drivers etc installed for the hardware that may be responsible for the problem.
I see you have a Logitech G510 keyboard
and unless I am mistaken also a
Razer Death Adder keyboard
are BOTH in use.
On my screenshots on post 23 as you can see all devices are shown there is no slide arrow to the right
On your playback devices - what else is listed please or is the space below the Dell Monitor all blank
I presume you have two Dell S27116DG monitors, is that correct please.