My DPI is set to the default (125%) for this screen at it's native resolution. It's a Dell lattitude laptop E6510 at 1920x1080. Control panel shows 125% as the Default.
I lowered the DPI to 'Smaller' which is 100% and the discloure arrows appeared, however the smaller fonts are not nice to look at, and hard to read, on this screen.
For reference windows calls 125% Default and 100% as 'Smaller'
Out of the box Windows would use 125% as default on this screen.
I hope this helps! If I can be of any more assistance, please feel free to ask.