I had the same problem, changing back to 96dpi corrected it. You have to remember not everybody who uses your software is young and have good eyesight. I have to change back to use everything with ease, 96dpi too small!
I did find the DPI setting, set it to 96 and now I see the OK and CANCEL buttons in the bottom right corner. Seems like a design a flaw to me. I can't use this monitor at 96 DPI. TEXT IS WAY TOO SMALL!!!!