With the latest drivers I cannot get the DSR drop down box to open when I click on it. It just says OFF and no other option shows.
Got your monitor OCd? My brother had the same problem yesterday, except DSR was disappearing in NVCP, although the resolutions were still available in game IIRC, it disappears for me when I use NV Surround too
Yea, when you OC your monitor for a higher refresh rate https://teksyndicate.com/node/134989 Obviously not the issue here if you didn't know about it though
Do you have Mouse Properties > Pointer Options > Automatically move pointer to the default button in a dialogue box option checked? If so then try unchecking it and it may fix the issue for you as it did for me when I was having problems selecting the DSR pulldown options.
They apparently don't care about many things. DSR being unusable in SLi for example, which is pretty mind boggling to be honest.