When you run a per-monitor, DPI-aware Windows Presentation Foundation (WPF) application on a high DPI setting (greater than 100 percent), the application is displayed at 100 percent DPI. This issue occurs if the target framework version of the application is earlier than 4.6.2, or if the operating system is earlier than Windows 10 Desktop Preview.
This issue also occurs in the XAML designer for UWP on Windows 8.1 applications in Visual Studio 2013 and Visual Studio 2015.
This issue also occurs in the XAML designer for UWP on Windows 8.1 applications in Visual Studio 2013 and Visual Studio 2015.