On Windows 8 with the screen resolution at 3840 x 2160, with the "Make text and other items larger or smaller" set to 150%, and dota2 set to fullscreen, the mouse pointers displayed locations, and the item highlighted and activated if you click is wrong.

With just eyeballing the distance for evidence, it would appear the displayed location is 150% further down and to the right of the registered location.

I could not repeat this with 2560 x 1600 or 1920 x 1080 monitors, even if the desktop scaling was set to 150%.