I've found a whole lot of basic display problems (bits of the screen not updating correctly, things being left displayed when they shouldn't be etc.), disappear if I set the emulation to use DX9, not DX10. This with quite basic Windows applications (Notepad for example). The whole display runs much better with the DX10 emulation disabled. This with a 2016 27" iMac i7, running Parallels as a window, placed on a second monitor. So, does the DX10 emulation actually work....
